Auto merge of #20211 - servo:derive-all-the-things, r=emilio

Improve #[derive(ToCss)]

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components/style/values/specified/box.rs

@@ -369,9 +369,9 @@ pub enum OverflowClipBox {
 pub enum WillChange {
     /// Expresses no particular intent
     Auto,
-    #[css(comma, iterable)]
     /// <custom-ident>
-    AnimateableFeatures(Box<[CustomIdent]>),
+    #[css(comma)]
+    AnimateableFeatures(#[css(iterable)] Box<[CustomIdent]>),
 }
 
 impl WillChange {

components/style/values/specified/counters.rs

@@ -92,8 +92,7 @@ pub enum Content {
     #[cfg(feature = "gecko")]
     MozAltContent,
     /// Content items.
-    #[css(iterable)]
-    Items(Box<[ContentItem]>),
+    Items(#[css(iterable)] Box<[ContentItem]>),
 }
 
 /// Items for the `content` property.

components/style/values/specified/font.rs

@@ -152,8 +152,8 @@ impl From<LengthOrPercentage> for FontSize {
 #[derive(Clone, Debug, Eq, Hash, PartialEq, ToCss)]
 pub enum FontFamily {
     /// List of `font-family`
-    #[css(iterable, comma)]
-    Values(FontFamilyList),
+    #[css(comma)]
+    Values(#[css(iterable)] FontFamilyList),
     /// System font
     System(SystemFont),
 }
@@ -718,11 +718,11 @@ pub enum VariantAlternates {
     #[css(function)]
     Stylistic(CustomIdent),
     /// Enables display with stylistic sets
-    #[css(comma, function, iterable)]
-    Styleset(Box<[CustomIdent]>),
+    #[css(comma, function)]
+    Styleset(#[css(iterable)] Box<[CustomIdent]>),
     /// Enables display of specific character variants
-    #[css(comma, function, iterable)]
-    CharacterVariant(Box<[CustomIdent]>),
+    #[css(comma, function)]
+    CharacterVariant(#[css(iterable)] Box<[CustomIdent]>),
     /// Enables display of swash glyphs
     #[css(function)]
     Swash(CustomIdent),