fix error in readme.txt

git-svn-id: https://plugins.svn.wordpress.org/linkwelove/trunk@815599 b8457f37-d9ea-0310-8a92-e5e31aec5664
another fix of readme

git-svn-id: https://plugins.svn.wordpress.org/linkwelove/trunk@815600 b8457f37-d9ea-0310-8a92-e5e31aec5664