style: Fix Servo build, and rustfmt recent changes.

components/style/properties/data.py

@@ -797,6 +797,7 @@ class PropertyRestrictions:
           + PropertyRestrictions.shorthand(data, "outline")
           + PropertyRestrictions.shorthand(data, "font"))
 
+
 class CountedUnknownProperty:
     def __init__(self, name):
         self.name = name

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

@@ -73,6 +73,7 @@
     }
 
     impl<'a> ToCss for LonghandsToSerialize<'a>  {
+        #[allow(unused)]
         fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
             use crate::values::specified::TextDecorationLine;