style: Run rustfmt on servo/components/style and servo/ports/geckolib

This patch is generated by running `cargo +nightly fmt` under
`servo/components/style/` and `servo/ports/geckolib` against mozilla-central
https://hg.mozilla.org/mozilla-central/rev/b193f2e7a6a5d1f042c957ea4acd5c89bf210512

My nightly version is: 1.58.0-nightly (c9c4b5d72 2021-11-17)

Manually remove the redundant braces in author_styles.rs to fix a warning.

Differential Revision: https://phabricator.services.mozilla.com/D131556

components/style/error_reporting.rs

@@ -214,7 +214,7 @@ impl<'a> fmt::Display for ContextualParseError<'a> {
             ContextualParseError::UnsupportedValue(_value, ref err) => parse_error_to_str(err, f),
             ContextualParseError::NeverMatchingHostSelector(ref selector) => {
                 write!(f, ":host selector is not featureless: {}", selector)
-            }
+            },
         }
     }
 }