docs(angular.element): css() method does not retrieve computed styles

The jQuery css() getter functionality utilises getComputedStyle() whereas
jqLite only retrieves what is declared inline on an element.

Closes angular#7599

Author: intellix

src/jqLite.js

@@ -44,7 +44,7 @@
  * - [`children()`](http://api.jquery.com/children/) - Does not support selectors
  * - [`clone()`](http://api.jquery.com/clone/)
  * - [`contents()`](http://api.jquery.com/contents/)
- * - [`css()`](http://api.jquery.com/css/)
+ * - [`css()`](http://api.jquery.com/css/) - Only retrieves inline-styles, does not call `getComputedStyles()`
  * - [`data()`](http://api.jquery.com/data/)
  * - [`detach()`](http://api.jquery.com/detach/)
  * - [`empty()`](http://api.jquery.com/empty/)