Merge request merge timing

Hello all, Recently there have been a few instances where merge requests were merged extremely quickly (e.g. within an hour of the MR being opened). While prompt review is a good thing, we also want to make sure that all potentially interested reviewers have an opportunity to comment. In this vein, I propose that we wait at least 24 hours from the time an MR is opened before sending it to Marge. I have documented this to the merge-request review guidelines on the Wiki [1]. Cheers, - Ben [1] https://gitlab.haskell.org/ghc/ghc/-/wikis/gitlab/merge-requests