Prevent admin breakage for `s` in `WP_Query` after [28623].

See #11330.


Built from https://develop.svn.wordpress.org/trunk@28666


git-svn-id: http://core.svn.wordpress.org/trunk@28484 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Avoid a PHP notice when using WP_Query::get_queried_object() in pre_get_posts action.

props wpsmith.
fixes #28412.
Built from https://develop.svn.wordpress.org/trunk@28667


git-svn-id: http://core.svn.wordpress.org/trunk@28485 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Move is_admin check to a more appropriate place.

see #11330.
Built from https://develop.svn.wordpress.org/trunk@28668


git-svn-id: http://core.svn.wordpress.org/trunk@28486 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add 'wp_title_parts' filter to wp_title().

props aaroncampbell, obenland.
fixes #17877.
Built from https://develop.svn.wordpress.org/trunk@28669


git-svn-id: http://core.svn.wordpress.org/trunk@28487 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add a filter to human_time_diff().

props slimndap.
fixes #27271.
Built from https://develop.svn.wordpress.org/trunk@28670


git-svn-id: http://core.svn.wordpress.org/trunk@28488 1a063a9b-81f0-0310-95a4-ce76da25c4cd