Replace $in_same_cat with $in_same_term in adjacent post functions for consistency.

props ixkaito.
fixes #28360.
Built from https://develop.svn.wordpress.org/trunk@28574


git-svn-id: http://core.svn.wordpress.org/trunk@28399 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix typo in [28574].

see #28360.
Built from https://develop.svn.wordpress.org/trunk@28575


git-svn-id: http://core.svn.wordpress.org/trunk@28400 1a063a9b-81f0-0310-95a4-ce76da25c4cd