Relies on simple heuristic for re-running setup

[igemnace]

#3 has been resolved by having makery#Setup run in a buffer-local manner, then running config detection with an autocommand on BufRead,BufNewFile.

While this works in the simple cases I've tested, it doesn't seem as robust as it can be. For comparison, Projectionist runs config detection on a long list of autocommand events.

While duplicating Projectionist's effort would be a waste (better to just do #5), some of those might be required to catch edge cases. Catching buftype in commit 1ac07e8 was already a concession here, for example, since without it, opening the quickfix kept bringing up Makery warnings.