pgsql: Improve internationalization of messages involving type names

Improve internationalization of messages involving type names

Change the slightly different variations of the message
function FOO must return type BAR
to a single wording, removing the variability in type name so that they
all create a single translation entry; since the type name is not to be
translated, there's no point in it being part of the message anyway.

Also, change them all to use the same quoting convention, namely that
the function name is not to be quoted but the type name is. (I'm not
quite sure why this is so, but it's the clear majority.)

Some similar messages such as "encoding conversion function FOO must ..."
are also changed.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/59a2111b23f6ceec4c777d68e20c1027d3c57c6f

Modified Files
--------------
src/backend/commands/conversioncmds.c | 4 ++--
src/backend/commands/event_trigger.c | 4 ++--
src/backend/commands/foreigncmds.c | 4 ++--
src/backend/commands/operatorcmds.c | 8 ++++----
src/backend/commands/proclang.c | 8 ++++----
src/backend/commands/trigger.c | 4 ++--
src/backend/commands/typecmds.c | 37 ++++++++++++++++++-----------------
src/backend/parser/parse_clause.c | 4 ++--
8 files changed, 37 insertions(+), 36 deletions(-)