As a software engineer, I'd love to see that someone is capable of putting effort into updating documentation, even with minor corrections and changes.

This is the kind of thing full time engineers typically don't enjoy doing, so docs stagnate and can quickly become out of date or inaccurate.

It's super useful if someone is used to a routine where they know how to dig into a project, find errors/inaccuracies, and work to improve them.

Fixing mistakes, typos, and errors are good things. Many articles and people suggest fixing typos in documentation for your first open source contributions. I would be interested if I found a new GitHub account with multiple accepted/pending PRs fixing things.

If they're presented as "I'm a code contributor" but it's solely non-code changes, then yes, it seems disingenuous at best.

But if they're accepted by the repo owner, they're probably not nonsense. And projects need better documentation. If the OP was applying for a junior 'tech' role of some sort, and demonstrated that experience of revising documentation to be up to date and improved... it's a step up from some people I've seen over the years (who leave behind bad/broken docs, for example).