Between 2.1.0 be released and my interview with NumFOCUS  we will hopefully be getting an influx of new contributors.
We should always be kind and respectful in pull requests (even if the person you are talking to 'can take it', potential contributors will read it and may be turned away), but please be extra patient with new contributors. I think everyone with commit rights can see "new contributor" next to the users name in the GH UI.
Remember that first contribution to a big project can be intimidating for many reasons, they may be simultaneously learning git, github, python, and the conventions of Matplotlib in addition to asking their work to be publicly judged by strangers! At least for my self, my first PR to Matplotlib was to change a 4 to a 7  and it still took me most of an afternoon to work up the nerve to open the PR.
For documentation only changes please use the threshold "Is it better than in was?" and avoid copy-editing-via-github comments.