dev.knotless.setAutoMerge

Sets an open pull to merge by itself once its checks pass, as `knotless pull merge --auto` does, as the account logged in to this appview's web pages: the owner and collaborators may, in a repository that names runners, into a branch with no merge queue. With undo, cancels it, as `--auto --undo` does: they and the pull's author may. Requires the session cookie the pages' login sets.