Minor: Fix an incorrect doc-comment and a superfluous IDE warning.

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@768991 b8457f37-d9ea-0310-8a92-e5e31aec5664
Minor: Add a note about intentional fall-through.

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@768994 b8457f37-d9ea-0310-8a92-e5e31aec5664