Clarify code review checklist instructions (PR #12056)
The intent of the checklist is to serve purely as a reminder, checking items communicates that you have considered the item, and have not accidentally forgotten about it.
Further, the checklist acts as a reminder for reviewers, unfortunately GitHub does not yet provide a way to create a dedicated code review template.
Additionally the wiki page has been adjusted: https://github.com/nvaccess/nvda/wiki/Github-pull-request-template-explanation-and-examples
Co-authored-by: Cyrille Bougot <cyrille.bougot2@laposte.net>
