libpq: Add missing OAuth translations

libpq: Add missing OAuth translations

Several strings that should have been translated as they passed through
libpq_gettext were not actually being pulled into the translation files,
because I hadn't directly wrapped them in one of the GETTEXT_TRIGGERS.

Move the responsibility for calling libpq_gettext() to the code that
sets actx->errctx. Doing the same in report_type_mismatch() would result
in double-translation, so mark those strings with gettext_noop()
instead. And wrap two ternary operands with gettext_noop(), even though
they're already in one of the triggers, since xgettext sees only the
first.

Finally, fe-auth-oauth.c was missing from nls.mk, so none of that file
was being translated at all. Add it now.

Original patch by Zhijie Hou, plus suggested tweaks by Álvaro Herrera
and small additions by me.

Reported-by: Zhijie Hou <houzj.fnst@fujitsu.com>
Author: Zhijie Hou <houzj.fnst@fujitsu.com>
Co-authored-by: Álvaro Herrera <alvherre@kurilemu.de>
Co-authored-by: Jacob Champion <jacob.champion@enterprisedb.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Discussion: https://postgr.es/m/TY4PR01MB1690746DB91991D1E9A47F57E94CDA%40TY4PR01MB16907.jpnprd01.prod.outlook.com
Backpatch-through: 18