Auto merge of #14457 - heycam:bindings-update-8, r=Manishearth

update stylo bindings

<!-- Please describe your changes on the following line: -->

Update stylo bindings for the latest mozilla-central sync.

r? @Manishearth

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components/style/binding_tools/regen.py

@@ -96,6 +96,7 @@
             "FrameRequestCallback",
             "gfxAlternateValue",
             "gfxFontFeature",
+            "gfxFontVariation",
             "GridNamedArea",
             "Image",
             "ImageURL",
@@ -291,7 +292,6 @@
             "nsIURI",
             "nsMainThreadPtrHolder",
             "nsRestyleHint",
-            "nsString",
             "nsStyleBackground",
             "nsStyleBorder",
             "nsStyleColor",

components/style/gecko_bindings/bindings.rs

@@ -970,6 +970,10 @@ extern "C" {
 extern "C" {
     pub fn Servo_Element_ClearData(node: RawGeckoElementBorrowed);
 }
+extern "C" {
+    pub fn Servo_Element_ShouldTraverse(node: RawGeckoElementBorrowed)
+     -> bool;
+}
 extern "C" {
     pub fn Servo_StyleSheet_Empty(parsing_mode: SheetParsingMode)
      -> RawServoStyleSheetStrong;
@@ -1102,7 +1106,8 @@ extern "C" {
                                                         RawServoDeclarationBlockBorrowed,
                                                     property: *mut nsIAtom,
                                                     is_custom: bool,
-                                                    buffer: *mut nsAString_internal);
+                                                    buffer:
+                                                        *mut nsAString_internal);
 }
 extern "C" {
     pub fn Servo_DeclarationBlock_Count(declarations: