I just found out that github has saved replies (https://help.github.com/articles/working-with-saved-replies/) If you are not yet using them try it, it might save you a lot of work!
I am tired of repeating myself when it comes to how new contributors should write a commit title/message, have only one commit, rebase on the latest changes, format their code, or point them to our or external resources to get more information, …
You can write detailed replies, save them and reuse them on comments, PR reviews, …
To set it up go to your github settings, then on your left in the menu hit
Saved replies and start writing.
Then on a PR when commenting you can select a reply by clicking the arrow