Add `notifications` and `BP_NOTIFICATIONS_SLUG` to `illegal_names` in `bp_core_get_illegal_names()`. Also add brackets for improved code readability.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7675 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Credits page: copy header text in from the updated About screen that was updated in r7674

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7676 cdf35c40-ae34-48e0-9cc9-0c9da1808c22