Add hook documentation in bp-friends-notifications.php.

Props tw2113.
See #5942.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9175 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Add hook documentation in bp-friends-template.php.

Props tw2113.
See #5942.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9176 cdf35c40-ae34-48e0-9cc9-0c9da1808c22