This is the sort of thing you have to learn by experience, like how you can't really learn good coding taste from reading a list of rules (though some lists are helpful).

Anyway in my experience documentation is quite different in public (i.e. seen by customers) and private (inside your company). For internal stuff there's a much smaller incentive to document things because:

1. documentation tends to be inconsistent (as you discovered), so people give up looking for it. Instead they just ask other people. This actually works fairly well inside a company because you can generally easily access whoever is responsible (as long as they haven't left).
2. there aren't customers to keep happy and away from support.

I think the best thing to do is to accept that people aren't going to expect documentation internally. There's zero point writing guides to tools on your company wiki or whatever, because nobody will even try to look for it - they'll assume it doesn't exist.

Instead you should try to keep your documentation as close to the user as possible. That means, don't have a separate docs folder in your repo - put your docs as comments in the code.

Don't put deployment instructions on your wiki - add a ./deploy.sh script. It can just echo the instructions initially.