pgsql: Remove no-longer-required function declarations.

Remove no-longer-required function declarations.

Remove a bunch of "extern Datum foo(PG_FUNCTION_ARGS);" declarations that
are no longer needed now that PG_FUNCTION_INFO_V1(foo) provides that.

Some of these were evidently missed in commit e7128e8dbb305059, but others
were cargo-culted in in code added since then.  Possibly that can be blamed
in part on the fact that we'd not fixed relevant documentation examples,
which I've now done.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/91e79260f636ab4d5a43910b6a38bc75651ad14c

Modified Files
--------------
contrib/hstore_plperl/hstore_plperl.c              |    2 --
contrib/hstore_plpython/hstore_plpython.c          |    2 --
contrib/ltree_plpython/ltree_plpython.c            |    1 -
contrib/pg_audit/pg_audit.c                        |    4 ----
doc/src/sgml/event-trigger.sgml                    |    2 --
doc/src/sgml/gist.sgml                             |    9 ---------
doc/src/sgml/trigger.sgml                          |    4 ----
src/backend/snowball/dict_snowball.c               |    2 --
.../conversion_procs/ascii_and_mic/ascii_and_mic.c |    3 ---
.../cyrillic_and_mic/cyrillic_and_mic.c            |   21 --------------------
.../euc2004_sjis2004/euc2004_sjis2004.c            |    3 ---
.../euc_cn_and_mic/euc_cn_and_mic.c                |    3 ---
.../euc_jp_and_sjis/euc_jp_and_sjis.c              |    7 -------
.../euc_kr_and_mic/euc_kr_and_mic.c                |    3 ---
.../euc_tw_and_big5/euc_tw_and_big5.c              |    7 -------
.../latin2_and_win1250/latin2_and_win1250.c        |    7 -------
.../conversion_procs/latin_and_mic/latin_and_mic.c |    7 -------
.../utf8_and_ascii/utf8_and_ascii.c                |    3 ---
.../conversion_procs/utf8_and_big5/utf8_and_big5.c |    3 ---
.../utf8_and_cyrillic/utf8_and_cyrillic.c          |    6 ------
.../utf8_and_euc2004/utf8_and_euc2004.c            |    3 ---
.../utf8_and_euc_cn/utf8_and_euc_cn.c              |    3 ---
.../utf8_and_euc_jp/utf8_and_euc_jp.c              |    3 ---
.../utf8_and_euc_kr/utf8_and_euc_kr.c              |    3 ---
.../utf8_and_euc_tw/utf8_and_euc_tw.c              |    3 ---
.../utf8_and_gb18030/utf8_and_gb18030.c            |    3 ---
.../conversion_procs/utf8_and_gbk/utf8_and_gbk.c   |    3 ---
.../utf8_and_iso8859/utf8_and_iso8859.c            |    3 ---
.../utf8_and_iso8859_1/utf8_and_iso8859_1.c        |    3 ---
.../utf8_and_johab/utf8_and_johab.c                |    3 ---
.../conversion_procs/utf8_and_sjis/utf8_and_sjis.c |    3 ---
.../utf8_and_sjis2004/utf8_and_sjis2004.c          |    3 ---
.../conversion_procs/utf8_and_uhc/utf8_and_uhc.c   |    3 ---
.../conversion_procs/utf8_and_win/utf8_and_win.c   |    3 ---
src/include/utils/jsonb.h                          |    6 +++---
src/tutorial/complex.c                             |   17 ----------------
src/tutorial/funcs_new.c                           |    9 ---------
37 files changed, 3 insertions(+), 170 deletions(-)