Add missing code formatting to navigator description (#2265)

Author: ddbeck

features/navigator.yml

@@ -1,5 +1,5 @@
 name: Navigator
-description: "The window.navigator API is a generic global object, under which many other, more interesting APIs are located. It doesn't do anything interesting on its own."
+description: "The `window.navigator` API is a generic global object, under which many other, more interesting APIs are located. It doesn't do anything interesting on its own."
 spec: https://html.spec.whatwg.org/multipage/system-state.html#the-navigator-object
 compat_features:
   - api.Navigator