docs(jqLite): Document that removeAttr doesn't support multiple attributes

jQuery supports removing multiple attributes in one go, jqLite doesn't.
This is now documented.

Author: mgol

src/jqLite.js

@@ -78,7 +78,7 @@
  * - [`prop()`](http://api.jquery.com/prop/)
  * - [`ready()`](http://api.jquery.com/ready/)
  * - [`remove()`](http://api.jquery.com/remove/)
- * - [`removeAttr()`](http://api.jquery.com/removeAttr/)
+ * - [`removeAttr()`](http://api.jquery.com/removeAttr/) - Does not support multiple attributes
  * - [`removeClass()`](http://api.jquery.com/removeClass/) - Does not support a function as first argument
  * - [`removeData()`](http://api.jquery.com/removeData/)
  * - [`replaceWith()`](http://api.jquery.com/replaceWith/)