Use wildcards instead of manually-maintained file lists in */nls.mk.

Use wildcards instead of manually-maintained file lists in */nls.mk.

The backend already used a mechanically-generated list of *.c files,
but everywhere else we had a manually-written-out list of files in
which to seek translatable messages.  Commit b0a55e432 contains the
latest in a long line of failures to update those lists.  Rather than
manually fix its oversight, let's change to using "$(wildcard *.c)"
in all these nls.mk files.

Many of these files also have manual references to some *.c files
in other directories, most often src/common/.  Perhaps we should try
to improve that situation too; but it's a bit less clear how, so for
now just fix the local file references.

Kyotaro Horiguchi and Tom Lane

Discussion: https://postgr.es/m/20220713.160853.453362706160476128.horikyota.ntt@gmail.com