Fix misc typos, mostly in comments

Heikki Linnakangas <heikki.linnakangas@iki.fi>

Commit: ad853bb877370d406864380491dfe95672867c98
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: 2026-01-08T16:10:08Z
Fix misc typos, mostly in comments

The only user-visible change is the fix in the "malformed
pg_dependencies" error detail. That one is new in commit e1405aa5e3ac,
so no backpatching required.

Files