Summary:
Add some postgres lint rules related to comments:

- bad_comment_style: C++ comment style uses //.  Postgres comment style
  is BSD style /* */.
- likely_bad_multiline_comment_start: multiline comments should have a
  lone /* and */ at the top and bottom.  There are a few exceptions that
  are explained in code comments.  This is a warning, not error, because
  upstream PG makes some mistakes.
- likely_bad_multiline_comment_end: for multiline comments, the last */
  should have asterisk aligned with the asterisk of the first /*.  This
  is a warning, not error, because upstream PG makes some mistakes.
Jira: DB-14577

Test Plan:
Close: #25360
Jenkins: skip

Reviewers: telgersma

Reviewed By: telgersma

Subscribers: telgersma, yql

Differential Revision: https://phorge.dev.yugabyte.com/D40760