Update comment about structure of items in $menu global.

props kitchin.
fixes #26635.

git-svn-id: https://develop.svn.wordpress.org/trunk@27151 602fd350-edb4-49c9-b593-d223f7449a82
Collect the post and link ids that will be reassigned before running the update in `remove_user_from_blog()`. Use `array_walk()` instead of `array_map()` when invalidating the caches for the collected ids.

Props kovshenin.
Fixes #25545.



git-svn-id: https://develop.svn.wordpress.org/trunk@27152 602fd350-edb4-49c9-b593-d223f7449a82