I often write and see written something like "Fix typo" in commit messages, when the fix was not in fact for a "typographical error". It might have been a duplicate word, a small grammatical problem (perhaps have/has, they're/their), an awkward construction, or a mistaken identifier. Is there a good, compact word or phrase that would describe this more accurately, but perhaps isn't as pretentious and hollow as "Fix minor linguistic problems"?
For a single generic phrasing, I'd suggest "correct text".
For more specific commit messages, "fix grammar", "fix spelling", "re-word message", or "rewrite text" could all be used.
The word "typo" is also used as a euphemism for any kind of writing error, especially for grammar errors, because hitting the wrong key is much less humiliating than making an error in grammar. It can be a subtle way of teaching someone a rule of grammar, assuming that he will think "huh?" and look it up if the rule is not mentioned.
As requested, adding this as an answer:
Actually, I would include duplicate words and homonym mistakes (they're/their, its/it's) as typos - they're cases where our fingers can't keep up with our brain, or is that vice versa. Basically, if it's something the original writer would have corrected if he'd had more time for/had paid more attention to proofreading, then it's a typo.
Copyedit as (nearly) suggesed in Colin Fine's answer is good. Also perhaps the briefer emend.
Another word I've seen used for something written in haste so it comes out wrong is thinko.
How about a simple 'Fix error'?
In the specific context of a checkin statement, words don't always mean the same thing as they would in a conversation or a contract. To a developer, "typo" means any time the letters on the screen don't match the thought in the head. Whether that's because the fingers got out of sync and you typed "teh" for "the", or a momentary brain-freeze had you typing "there" for "their", or even that you personally are sure it's "seperator" even though everyone else writes "separator", they are all likely to be lumped together as typos. When a checkin comment says "fix typos" I know that it means there is no deep meaning to look for here, just somebody tweaking a comment or an error message or the like.
My favourite checkin comment ever, btw, was "fix tyos". Not deliberate either. Just someone in a hurry :-)
I would say "Copy-edit".
(Extra text to make my answer long enough to be accepted)
Correct a misspelling maybe?
"Correct the grammatos in this for me please" could be what you are looking for.
Example: Fix this grammato for me, will you?
- Core ect clum sines
- Corect clumsines
- Corretc clumsines
- Correct clumsiness