Add a lint rule forbidding use of "each()"

Summary:
Ref T13588. "each()" has been a bad idea for a long time, and was formally deprecated in PHP 7.2 and removed in PHP 8.0.

Catch use of "each()" in lint and reject it.

Test Plan:
Added and ran unit tests.

Subscribers: cspeckmim

Maniphest Tasks: T13588

Differential Revision: https://secure.phabricator.com/D21741