if you're as clumsy as i am and this happens to you often; you'd be needing this a lot.
i find myself mistakenly pushing folders i don't want to github/gitlab and there's really no easy way of removing such from the web clients so i keep having to search for ways to do this every single time and for this reason i will be writing it down here so i can easily just refer to it.
Removing Folder from Git While Keeping it on Local
this can be easily done by;
git rm -r --cached folder-name
after running the command; a git add, commit and push should do the rest of the job easily.
Removing Folder from Both Git and Local
git rm -r folder-name
after running this also, like the previous one; a commit and push would take care of the rest
hope this helps future me, and you.