Improve error message with JSON_SERIALIZE()

The error message introduced in 3c633f3 can share the same format string
with an existing message used for JSON(), reducing the translation
effort.

Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20220708.154135.2123613118233840495.horikyota.ntt@gmail.com
Backpatch-through: 15

src/backend/parser/parse_expr.c

@@ -4587,8 +4587,9 @@ transformJsonSerializeExpr(ParseState *pstate, JsonSerializeExpr *expr)
 			if (typcategory != TYPCATEGORY_STRING)
 				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("cannot use RETURNING type %s in JSON_SERIALIZE",
-								format_type_be(returning->typid)),
+						 errmsg("cannot use RETURNING type %s in %s",
+								format_type_be(returning->typid),
+								"JSON_SERIALIZE()"),
 						 errhint("Try returning a string type or bytea")));
 		}
 	}

src/test/regress/expected/sqljson.out

@@ -316,7 +316,7 @@ SELECT pg_typeof(JSON_SERIALIZE(NULL));
 
 -- only string types or bytea allowed
 SELECT JSON_SERIALIZE('{ "a" : 1 } ' RETURNING jsonb);
-ERROR:  cannot use RETURNING type jsonb in JSON_SERIALIZE
+ERROR:  cannot use RETURNING type jsonb in JSON_SERIALIZE()
 HINT:  Try returning a string type or bytea
 EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_SERIALIZE('{}');
                      QUERY PLAN