minor change to readme

git-svn-id: https://plugins.svn.wordpress.org/better-admin-pointers/trunk@926103 b8457f37-d9ea-0310-8a92-e5e31aec5664
minor change to readme

git-svn-id: https://plugins.svn.wordpress.org/better-admin-pointers/trunk@926106 b8457f37-d9ea-0310-8a92-e5e31aec5664