Mark to_tsvector(regconfig,json[b]) functions immutable

This make them consistent with the text function and means they can be
used in functional indexes.

Catalog version bumped.

Per gripe from Josh Berkus.

Author: adunstan

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201705301
+#define CATALOG_VERSION_NO	201706081
 
 #endif

src/include/catalog/pg_proc.h

@@ -4871,9 +4871,9 @@ DATA(insert OID = 4209 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f s s
 DESCR("transform jsonb to tsvector");
 DATA(insert OID = 4210 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f s s 1 0 3614 "114" _null_ _null_ _null_ _null_ _null_ json_to_tsvector _null_ _null_ _null_ ));
 DESCR("transform json to tsvector");
-DATA(insert OID = 4211 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f s s 2 0 3614 "3734 3802" _null_ _null_ _null_ _null_ _null_ jsonb_to_tsvector_byid _null_ _null_ _null_ ));
+DATA(insert OID = 4211 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f i s 2 0 3614 "3734 3802" _null_ _null_ _null_ _null_ _null_ jsonb_to_tsvector_byid _null_ _null_ _null_ ));
 DESCR("transform jsonb to tsvector");
-DATA(insert OID = 4212 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f s s 2 0 3614 "3734 114" _null_ _null_ _null_ _null_ _null_ json_to_tsvector_byid _null_ _null_ _null_ ));
+DATA(insert OID = 4212 (  to_tsvector		PGNSP PGUID 12 100 0 0 0 f f f f t f i s 2 0 3614 "3734 114" _null_ _null_ _null_ _null_ _null_ json_to_tsvector_byid _null_ _null_ _null_ ));
 DESCR("transform json to tsvector");
 
 DATA(insert OID = 3752 (  tsvector_update_trigger			PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 2279 "" _null_ _null_ _null_ _null_ _null_ tsvector_update_trigger_byid _null_ _null_ _null_ ));