Split font-synthesis into many features in a group

Trying to compute the status of the previous font-synthesis feature
proved it to be untenable as a single feature, or as features that pair
`font-synthesis: style` with `font-synthesis-style`. Define a bunch of
new features, and gently discourage use of the shorthand in the
description.

See w3c/csswg-drafts#1641 for background.

feature-group-definitions/font-synthesis-position.dist.yml

@@ -0,0 +1,19 @@
+# Generated from: font-synthesis-position.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+name: font-synthesis-position
+description: "The `font-synthesis-position` CSS property sets whether or not the browser should synthesize subscript and superscript typefaces when they're missing from the font."
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-position
+group: font-synthesis
+status:
+  baseline: false
+  support:
+    firefox: "118"
+    firefox_android: "118"
+compat_features:
+  - css.properties.font-synthesis-position
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: position`
+  # affects everything except position, and doesn't fit the description of this
+  # feature. See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.position

feature-group-definitions/font-synthesis-position.yml

@@ -0,0 +1,11 @@
+name: font-synthesis-position
+description: "The `font-synthesis-position` CSS property sets whether or not the browser should synthesize subscript and superscript typefaces when they're missing from the font."
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-position
+group: font-synthesis
+compat_features:
+  - css.properties.font-synthesis-position
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: position`
+  # affects everything except position, and doesn't fit the description of this
+  # feature. See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.position

feature-group-definitions/font-synthesis-small-caps.dist.yml

@@ -0,0 +1,26 @@
+# Generated from: font-synthesis-small-caps.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+name: font-synthesis-small-caps
+description: "The `font-synthesis-small-caps` CSS property sets whether or not the browser should synthesize small caps typefaces when they're missing from the font."
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-small-caps
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/703
+status:
+  baseline: low
+  baseline_low_date: 2023-03-27
+  support:
+    chrome: "97"
+    chrome_android: "97"
+    edge: "97"
+    firefox: "111"
+    firefox_android: "111"
+    safari: "16.4"
+    safari_ios: "16.4"
+compat_features:
+  - css.properties.font-synthesis-small-caps
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: small-caps`
+  # affects everything except small caps, and doesn't fit the description of
+  # this feature. See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.small-caps

feature-group-definitions/font-synthesis-small-caps.yml

@@ -0,0 +1,12 @@
+name: font-synthesis-small-caps
+description: "The `font-synthesis-small-caps` CSS property sets whether or not the browser should synthesize small caps typefaces when they're missing from the font."
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-small-caps
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/703
+compat_features:
+  - css.properties.font-synthesis-small-caps
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: small-caps`
+  # affects everything except small caps, and doesn't fit the description of
+  # this feature. See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.small-caps

feature-group-definitions/font-synthesis-style.dist.yml

@@ -0,0 +1,26 @@
+# Generated from: font-synthesis-style.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+name: font-synthesis-style
+description: The `font-synthesis-style` CSS property sets whether or not the browser should synthesize italic and oblique typefaces when they're missing from the font.
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-style
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/701
+status:
+  baseline: low
+  baseline_low_date: 2023-03-27
+  support:
+    chrome: "97"
+    chrome_android: "97"
+    edge: "97"
+    firefox: "111"
+    firefox_android: "111"
+    safari: "16.4"
+    safari_ios: "16.4"
+compat_features:
+  - css.properties.font-synthesis-style
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: style` affects
+  # everything except style, and doesn't fit the description of this feature.
+  # See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.style

feature-group-definitions/font-synthesis-style.yml

@@ -0,0 +1,12 @@
+name: font-synthesis-style
+description: The `font-synthesis-style` CSS property sets whether or not the browser should synthesize italic and oblique typefaces when they're missing from the font.
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-style
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/701
+compat_features:
+  - css.properties.font-synthesis-style
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: style` affects
+  # everything except style, and doesn't fit the description of this feature.
+  # See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.style

feature-group-definitions/font-synthesis-weight.dist.yml

@@ -0,0 +1,26 @@
+# Generated from: font-synthesis-weight.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+name: font-synthesis-weight
+description: The `font-synthesis-weight` CSS property sets whether or not the browser should synthesize bold typefaces when they're missing from the font.
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-weight
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/700
+status:
+  baseline: low
+  baseline_low_date: 2023-03-27
+  support:
+    chrome: "97"
+    chrome_android: "97"
+    edge: "97"
+    firefox: "111"
+    firefox_android: "111"
+    safari: "16.4"
+    safari_ios: "16.4"
+compat_features:
+  - css.properties.font-synthesis-weight
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: weight` affects
+  # everything except weight, and doesn't fit the description of this feature.
+  # See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.weight

feature-group-definitions/font-synthesis-weight.yml

@@ -0,0 +1,12 @@
+name: font-synthesis-weight
+description: The `font-synthesis-weight` CSS property sets whether or not the browser should synthesize bold typefaces when they're missing from the font.
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-weight
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/700
+compat_features:
+  - css.properties.font-synthesis-weight
+  # The font-synthesis shorthand also allows disabling all synthesis and opting
+  # in to specific kinds of synthesis. As such, `font-synthesis: weight` affects
+  # everything except weight, and doesn't fit the description of this feature.
+  # See https://github.com/w3c/csswg-drafts/issues/1641.
+  # - css.properties.font-synthesis.weight

feature-group-definitions/font-synthesis.dist.yml

@@ -0,0 +1,21 @@
+# Generated from: font-synthesis.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+name: font-synthesis
+description: The `font-synthesis` CSS shorthand property disables all font synthesis except the given kinds. To disable synthesis of a specific kind of font synthesis, instead use the longhand properties such as `font-synthesis-style` and `font-synthesis-weight`.
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/704
+status:
+  baseline: low
+  baseline_low_date: 2022-01-06
+  support:
+    chrome: "97"
+    chrome_android: "97"
+    edge: "97"
+    firefox: "34"
+    firefox_android: "34"
+    safari: "9"
+    safari_ios: "9"
+compat_features:
+  - css.properties.font-synthesis

feature-group-definitions/font-synthesis.yml

@@ -1,18 +1,7 @@
 name: font-synthesis
-description: The `font-synthesis` CSS property sets whether or not the browser should synthesize bold, italic, small-caps, and other typefaces when they're missing from the font.
-spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-intro
-usage_stats:
-  - https://chromestatus.com/metrics/css/timeline/popularity/700 # font-synthesis-weight
-  - https://chromestatus.com/metrics/css/timeline/popularity/701 # font-synthesis-style
-  - https://chromestatus.com/metrics/css/timeline/popularity/703 # font-synthesis-small-caps
-  - https://chromestatus.com/metrics/css/timeline/popularity/704 # font-synthesis
+description: The `font-synthesis` CSS shorthand property disables all font synthesis except the given kinds. To disable synthesis of a specific kind of font synthesis, instead use the longhand properties such as `font-synthesis-style` and `font-synthesis-weight`.
+spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis
+group: font-synthesis
+usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/704
 compat_features:
-  - css.properties.font-synthesis-position
-  - css.properties.font-synthesis-small-caps
-  - css.properties.font-synthesis-style
-  - css.properties.font-synthesis-weight
   - css.properties.font-synthesis
-  - css.properties.font-synthesis.position
-  - css.properties.font-synthesis.small-caps
-  - css.properties.font-synthesis.style
-  - css.properties.font-synthesis.weight

groups/css.yml

@@ -0,0 +1,7 @@
+# This group is intended for everything that can be done with CSS syntax and its
+# associated APIs. Almost all such features are defined by the CSSWG, but there
+# are exceptions: https://compat.spec.whatwg.org/#css-compat-section
+#
+# Additionally, not every deliverable of the CSSWG is a CSS feature:
+# https://drafts.fxtf.org/geometry/
+name: CSS

groups/font-synthesis.yml

@@ -0,0 +1,3 @@
+# https://drafts.csswg.org/css-fonts-4/#font-synthesis-intro
+name: Font synthesis
+parent: fonts

groups/fonts.yml

@@ -0,0 +1,3 @@
+# Everything related to web fonts and font rendering control.
+name: Fonts
+parent: css