am 92dbad8a: am b4d2e42a: docs: revise menu guide to focus more on using menu resources instead of defining menus in code. And revise some style.

Merge commit '92dbad8ab0c8e242c4c3e52c339ed3296ae7901c' into gingerbread-plus-aosp

* commit '92dbad8ab0c8e242c4c3e52c339ed3296ae7901c':
  docs: revise menu guide to focus more on using menu resources