Format list of catalog files in makefile vertically
This makes it easier to compare the lists visually with the
corresponding meson lists.
In passing, copy over some relevant comments from the makefiles to
meson.build.
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://www.postgresql.org/message-id/flat/
a306be82-ee71-4554-d499-
49a45a654396%40eisentraut.org