style: Trivial indentation fix.

MozReview-Commit-ID: JqBxF7i0HQZ

components/style/properties/properties.mako.rs

@@ -1490,7 +1490,7 @@ impl UnparsedValue {
             PropertyDeclaration::CSSWideKeyword(WideKeywordDeclaration {
                 id: longhand_id,
                 keyword,
-        })
+            })
         })
     }
 }