This change renames `$new_whitelist_options` to `$new_allowed_options`. This makes the variable’s purpose more clear, and promotes using more inclusive language.
For backwards compatibility, the new variable is passed by reference to the old one.
Follow up to [48121].
Props ayeshrajans, desrosj, jorbin, SergeyBiryukov.
See #50413.
Fixes#50434.
git-svn-id: https://develop.svn.wordpress.org/trunk@48477 602fd350-edb4-49c9-b593-d223f7449a82