style: Remove moz-prefixed aliases for column-gap and CSS multi-colum…

…n properties.

Introduce a new pref "layout.css.prefixes.columns" to guard the prefixed
aliases.

The modification to `properties-db.js` was generated by
`./mach devtools-css-db`.

Differential Revision: https://phabricator.services.mozilla.com/D59564

components/style/properties/longhands/column.mako.rs

@@ -13,7 +13,7 @@ ${helpers.predefined_type(
     engines="gecko servo-2013 servo-2020",
     servo_2020_pref="layout.2020.unimplemented",
     initial_specified_value="specified::length::NonNegativeLengthOrAuto::auto()",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     animation_value_type="NonNegativeLengthOrAuto",
     servo_2013_pref="layout.columns.enabled",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-width",
@@ -29,7 +29,7 @@ ${helpers.predefined_type(
     initial_specified_value="specified::ColumnCount::auto()",
     servo_2013_pref="layout.columns.enabled",
     animation_value_type="AnimatedColumnCount",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-count",
     servo_restyle_damage="rebuild_and_reflow",
 )}
@@ -38,7 +38,7 @@ ${helpers.single_keyword(
     "column-fill",
     "balance auto",
     engines="gecko",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     animation_value_type="discrete",
     gecko_enum_prefix="StyleColumnFill",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-fill",
@@ -53,7 +53,7 @@ ${helpers.predefined_type(
     computed_type="crate::values::computed::NonNegativeLength",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule-width",
     animation_value_type="NonNegativeLength",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
 )}
 
 // https://drafts.csswg.org/css-multicol-1/#crc
@@ -64,7 +64,7 @@ ${helpers.predefined_type(
     engines="gecko",
     initial_specified_value="specified::Color::currentcolor()",
     animation_value_type="AnimatedColor",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     ignored_when_colors_disabled=True,
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule-color",
 )}
@@ -76,7 +76,7 @@ ${helpers.single_keyword(
     animation_value_type="discrete",
     gecko_enum_prefix="StyleColumnSpan",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-span",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
 )}
 
 ${helpers.predefined_type(
@@ -86,7 +86,7 @@ ${helpers.predefined_type(
     engines="gecko",
     needs_context=False,
     initial_specified_value="specified::BorderStyle::None",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     animation_value_type="discrete",
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule-style",
 )}

components/style/properties/longhands/position.mako.rs

@@ -398,7 +398,7 @@ ${helpers.predefined_type(
     "computed::length::NonNegativeLengthPercentageOrNormal::normal()",
     engines="gecko servo-2013",
     alias="grid-column-gap" if engine == "gecko" else "",
-    extra_prefixes="moz",
+    extra_prefixes="moz:layout.css.prefixes.columns",
     servo_2013_pref="layout.columns.enabled",
     spec="https://drafts.csswg.org/css-align-3/#propdef-column-gap",
     animation_value_type="NonNegativeLengthPercentageOrNormal",

components/style/properties/shorthands/column.mako.rs

@@ -9,7 +9,8 @@
                     sub_properties="column-width column-count"
                     servo_2013_pref="layout.columns.enabled",
                     derive_serialize="True"
-                    extra_prefixes="moz" spec="https://drafts.csswg.org/css-multicol/#propdef-columns">
+                    extra_prefixes="moz:layout.css.prefixes.columns"
+                    spec="https://drafts.csswg.org/css-multicol/#propdef-columns">
     use crate::properties::longhands::{column_count, column_width};
 
     pub fn parse_value<'i, 't>(
@@ -59,7 +60,7 @@
 <%helpers:shorthand
     name="column-rule"
     engines="gecko"
-    extra_prefixes="moz"
+    extra_prefixes="moz:layout.css.prefixes.columns"
     sub_properties="column-rule-width column-rule-style column-rule-color"
     derive_serialize="True"
     spec="https://drafts.csswg.org/css-multicol/#propdef-column-rule"