On the same reasoning as in commit 36b93121, forbid using custom
oid_symbol macros in pg_type as well as pg_proc, so that we always
rely on the predictable macro names generated by genbki.pl.

We do continue to grant grandfather status to the names CASHOID and
LSNOID, although those are now considered deprecated aliases for the
preferred names MONEYOID and PG_LSNOID.  This is because there's
likely to be client-side code using the old names, and this bout of
neatnik-ism doesn't quite seem worth breaking client code.

There might be a case for grandfathering EVTTRIGGEROID, too, since
externally-maintained PLs may reference that symbol.  But renaming
such references to EVENT_TRIGGEROID doesn't seem like a particularly
heavy lift --- we make far more significant backend API changes in
every major release.  For now I didn't add that, but we could
reconsider if there's pushback.

The other names changed here seem pretty unlikely to have any outside
uses.  Again, we could add alias macros if there are complaints, but
for now I didn't.

As before, no need for a catversion bump.

John Naylor

Discussion: https://postgr.es/m/CAFBsxsHpCbjfoddNGpnnnY5pHwckWfiYkMYSF74PmP1su0+ZOw@mail.gmail.com