pgsql: Add to_regprocedure() and to_regoperator().

Add to_regprocedure() and to_regoperator().

These are natural complements to the functions added by commit
0886fc6a5c75b294544263ea979b9cf6195407d9, but they weren't included
in the original patch for some reason.  Add them.

Patch by me, per a complaint by Tom Lane.  Review by Tatsuo
Ishii.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/dfc0219f649d5450a5e4d491dab1eeb23ac5530a

Modified Files
--------------
doc/src/sgml/func.sgml                |   28 +++++++++--
src/backend/utils/adt/regproc.c       |   71 ++++++++++++++++++++++++++++
src/include/catalog/catversion.h      |    2 +-
src/include/catalog/pg_proc.h         |    4 ++
src/include/utils/builtins.h          |    2 +
src/test/regress/expected/regproc.out |   82 +++++++++++++++++++++++++++++++++
src/test/regress/sql/regproc.sql      |   15 ++++++
7 files changed, 199 insertions(+), 5 deletions(-)