New users sometimes are still getting the hang of the editing feature and may attempt something like this; but they don’t get their edit in automatically, it has to be approved, and I for one would reject such an edit as too minor. But that is not the case here.
Setting that aside:
For old questions that have not had activity recently, minor edits like this would be strongly discouraged (in my opinion) because they cause the question to jump up in the “active” queue for no good reason. But they can’t really be “prohibited”; one hopes established users know better than to do so.
Again, that is not the situation here: this is a recent question that had been having sufficient activity to keep it “around”.
So... well, speaking for myself, I am a stickler for good formatting and for grammar. I often have to actively stop myself from making edits that seem minor. Sometimes I edit just to change a
\pmod, or a
sin to a
\sin. But there is nothing inherently wrong from making an edit that improves the post, no matter in how much of a minor way, provided again that you are dealing with a something that has been not been dormant for a while so you aren’t just kicking it up the queue for no good reason.