> my supervisor constantly made edits that seemed to me unnecessary, almost as if he felt it was required of him to demonstrate his mastery.

There are many stories of savvy workers engaging proactively including a flaw in their work being reviewed, something small but obvious and easy to fix, so that their managers can feel involved. One that often comes up in software is an apocryphal "duck" in an unreleased attack animation for the queen-unit in Interplay's Battle Chess game.

Closely related are the appearance of changes, such as a tale that Michelangelo was pressured to "fix" the nose of his David statue, so he climbed up and knocked off a little bit of material and the superior down below was satisfied without being able to verify anything had really changed.