correct markdown readme

git-svn-id: https://plugins.svn.wordpress.org/very-basic-content-restriction/trunk@821071 b8457f37-d9ea-0310-8a92-e5e31aec5664
correct markdown readme

git-svn-id: https://plugins.svn.wordpress.org/very-basic-content-restriction/trunk@821073 b8457f37-d9ea-0310-8a92-e5e31aec5664