The wiki has this page on translations with a bunch of links.
[https://gitlab.gnome.org/Teams/Translation](This is where you can report mistranslations). You'll need to register an account (or log in with Google/Github/Gitlab.com). Then you can browse to your language (i.e. this page). Go to the issues list in the toolbar on the left, and create new issue with the blue button on the top right.
Hey, thanks for your detailed explanation. I was kinda lost at first with all those directories that don't seem relevant to translations, but your link to the document cleared things up. you just saved me hours of randomly searching directories for my PR. You're a total hero