Improve procost estimates for some text search functions.

The text search functions that involve parsing raw text into lexemes are
remarkably CPU-intensive, so estimating them at the same cost as most other
built-in functions seems like a mistake; moreover, doing so turns out to
discourage the optimizer from using functional indexes on these functions.
After some debate, we've agreed to raise procost from 1 to 100 for
to_tsvector(), plainto_tsvector(), to_tsquery(), ts_headline(),
ts_match_tt(), and ts_match_tq(), which are all the text search functions
that parse raw text.

Also increase procost for the 2-argument form of ts_rewrite()
(tsquery_rewrite_query); while this function doesn't do text parsing,
it does execute a user-supplied SQL query, so its previous procost of 1 is
clearly a drastic underestimate.  It seems reasonable to assign it the same
cost we assign to PL functions by default, so 100 is the number here too.

I did not bother bumping catversion for this change, since it does not
break catalog compatibility with the server executable nor result in
any regression test changes.

Per complaint from Andrew Gierth and subsequent discussion.

src/include/catalog/pg_proc.h

@@ -4494,8 +4494,8 @@ DATA(insert OID = 3625 (  tsvector_concat		PGNSP PGUID 12 1 0 0 0 f f f f t f i
 
 DATA(insert OID = 3634 (  ts_match_vq			PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 16 "3614 3615" _null_ _null_ _null_ _null_ _null_ ts_match_vq _null_ _null_ _null_ ));
 DATA(insert OID = 3635 (  ts_match_qv			PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 16 "3615 3614" _null_ _null_ _null_ _null_ _null_ ts_match_qv _null_ _null_ _null_ ));
-DATA(insert OID = 3760 (  ts_match_tt			PGNSP PGUID 12 3 0 0 0 f f f f t f s 2 0 16 "25 25" _null_ _null_ _null_ _null_ _null_ ts_match_tt _null_ _null_ _null_ ));
-DATA(insert OID = 3761 (  ts_match_tq			PGNSP PGUID 12 2 0 0 0 f f f f t f s 2 0 16 "25 3615" _null_ _null_ _null_ _null_ _null_ ts_match_tq _null_ _null_ _null_ ));
+DATA(insert OID = 3760 (  ts_match_tt			PGNSP PGUID 12 100 0 0 0 f f f f t f s 2 0 16 "25 25" _null_ _null_ _null_ _null_ _null_ ts_match_tt _null_ _null_ _null_ ));
+DATA(insert OID = 3761 (  ts_match_tq			PGNSP PGUID 12 100 0 0 0 f f f f t f s 2 0 16 "25 3615" _null_ _null_ _null_ _null_ _null_ ts_match_tq _null_ _null_ _null_ ));
 
 DATA(insert OID = 3648 (  gtsvector_compress	PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 2281 "2281" _null_ _null_ _null_ _null_ _null_ gtsvector_compress _null_ _null_ _null_ ));
 DESCR("GiST tsvector support");
@@ -4554,7 +4554,7 @@ DESCR("show real useful query for GiST index");
 
 DATA(insert OID = 3684 (  ts_rewrite		PGNSP PGUID 12 1 0 0 0 f f f f t f i 3 0 3615 "3615 3615 3615" _null_ _null_ _null_ _null_ _null_ tsquery_rewrite _null_ _null_ _null_ ));
 DESCR("rewrite tsquery");
-DATA(insert OID = 3685 (  ts_rewrite		PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 3615 "3615 25" _null_ _null_ _null_ _null_ _null_ tsquery_rewrite_query _null_ _null_ _null_ ));
+DATA(insert OID = 3685 (  ts_rewrite		PGNSP PGUID 12 100 0 0 0 f f f f t f v 2 0 3615 "3615 25" _null_ _null_ _null_ _null_ _null_ tsquery_rewrite_query _null_ _null_ _null_ ));
 DESCR("rewrite tsquery");
 
 DATA(insert OID = 3695 (  gtsquery_compress				PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 2281 "2281" _null_ _null_ _null_ _null_ _null_ gtsquery_compress _null_ _null_ _null_ ));
@@ -4644,26 +4644,26 @@ DESCR("(internal)");
 DATA(insert OID = 3741 (  thesaurus_lexize	PGNSP PGUID 12 1 0 0 0 f f f f t f i 4 0 2281 "2281 2281 2281 2281" _null_ _null_ _null_ _null_ _null_ thesaurus_lexize _null_ _null_ _null_ ));
 DESCR("(internal)");
 
-DATA(insert OID = 3743 (  ts_headline	PGNSP PGUID 12 1 0 0 0 f f f f t f i 4 0 25 "3734 25 3615 25" _null_ _null_ _null_ _null_ _null_ ts_headline_byid_opt _null_ _null_ _null_ ));
+DATA(insert OID = 3743 (  ts_headline	PGNSP PGUID 12 100 0 0 0 f f f f t f i 4 0 25 "3734 25 3615 25" _null_ _null_ _null_ _null_ _null_ ts_headline_byid_opt _null_ _null_ _null_ ));
 DESCR("generate headline");
-DATA(insert OID = 3744 (  ts_headline	PGNSP PGUID 12 1 0 0 0 f f f f t f i 3 0 25 "3734 25 3615" _null_ _null_ _null_ _null_ _null_ ts_headline_byid _null_ _null_ _null_ ));
+DATA(insert OID = 3744 (  ts_headline	PGNSP PGUID 12 100 0 0 0 f f f f t f i 3 0 25 "3734 25 3615" _null_ _null_ _null_ _null_ _null_ ts_headline_byid _null_ _null_ _null_ ));
 DESCR("generate headline");
-DATA(insert OID = 3754 (  ts_headline	PGNSP PGUID 12 1 0 0 0 f f f f t f s 3 0 25 "25 3615 25" _null_ _null_ _null_ _null_ _null_ ts_headline_opt _null_ _null_ _null_ ));
+DATA(insert OID = 3754 (  ts_headline	PGNSP PGUID 12 100 0 0 0 f f f f t f s 3 0 25 "25 3615 25" _null_ _null_ _null_ _null_ _null_ ts_headline_opt _null_ _null_ _null_ ));
 DESCR("generate headline");
-DATA(insert OID = 3755 (  ts_headline	PGNSP PGUID 12 1 0 0 0 f f f f t f s 2 0 25 "25 3615" _null_ _null_ _null_ _null_ _null_ ts_headline _null_ _null_ _null_ ));
+DATA(insert OID = 3755 (  ts_headline	PGNSP PGUID 12 100 0 0 0 f f f f t f s 2 0 25 "25 3615" _null_ _null_ _null_ _null_ _null_ ts_headline _null_ _null_ _null_ ));
 DESCR("generate headline");
 
-DATA(insert OID = 3745 (  to_tsvector		PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3614 "3734 25" _null_ _null_ _null_ _null_ _null_ to_tsvector_byid _null_ _null_ _null_ ));
+DATA(insert OID = 3745 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f i 2 0 3614 "3734 25" _null_ _null_ _null_ _null_ _null_ to_tsvector_byid _null_ _null_ _null_ ));
 DESCR("transform to tsvector");
-DATA(insert OID = 3746 (  to_tsquery		PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3615 "3734 25" _null_ _null_ _null_ _null_ _null_ to_tsquery_byid _null_ _null_ _null_ ));
+DATA(insert OID = 3746 (  to_tsquery		PGNSP PGUID 12 100 0 0 0 f f f f t f i 2 0 3615 "3734 25" _null_ _null_ _null_ _null_ _null_ to_tsquery_byid _null_ _null_ _null_ ));
 DESCR("make tsquery");
-DATA(insert OID = 3747 (  plainto_tsquery	PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 3615 "3734 25" _null_ _null_ _null_ _null_ _null_ plainto_tsquery_byid _null_ _null_ _null_ ));
+DATA(insert OID = 3747 (  plainto_tsquery	PGNSP PGUID 12 100 0 0 0 f f f f t f i 2 0 3615 "3734 25" _null_ _null_ _null_ _null_ _null_ plainto_tsquery_byid _null_ _null_ _null_ ));
 DESCR("transform to tsquery");
-DATA(insert OID = 3749 (  to_tsvector		PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 3614 "25" _null_ _null_ _null_ _null_ _null_ to_tsvector _null_ _null_ _null_ ));
+DATA(insert OID = 3749 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f s 1 0 3614 "25" _null_ _null_ _null_ _null_ _null_ to_tsvector _null_ _null_ _null_ ));
 DESCR("transform to tsvector");
-DATA(insert OID = 3750 (  to_tsquery		PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 3615 "25" _null_ _null_ _null_ _null_ _null_ to_tsquery _null_ _null_ _null_ ));
+DATA(insert OID = 3750 (  to_tsquery		PGNSP PGUID 12 100 0 0 0 f f f f t f s 1 0 3615 "25" _null_ _null_ _null_ _null_ _null_ to_tsquery _null_ _null_ _null_ ));
 DESCR("make tsquery");
-DATA(insert OID = 3751 (  plainto_tsquery	PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 3615 "25" _null_ _null_ _null_ _null_ _null_ plainto_tsquery _null_ _null_ _null_ ));
+DATA(insert OID = 3751 (  plainto_tsquery	PGNSP PGUID 12 100 0 0 0 f f f f t f s 1 0 3615 "25" _null_ _null_ _null_ _null_ _null_ plainto_tsquery _null_ _null_ _null_ ));
 DESCR("transform to tsquery");
 
 DATA(insert OID = 3752 (  tsvector_update_trigger			PGNSP PGUID 12 1 0 0 0 f f f f f f v 0 0 2279 "" _null_ _null_ _null_ _null_ _null_ tsvector_update_trigger_byid _null_ _null_ _null_ ));