pgstat: reorder pgstat.[ch] contents.
Now that
13619598f10 has split pgstat up into multiple files it isn't quite as
hard to come up with a sensible order for pgstat.[ch]. Inconsistent naming
makes it still not quite right looking, but that's work for another commit.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/
20220303021600.hs34ghqcw6zcokdh@alap3.anarazel.de