Fix misleading error message about inconsistent moving-aggregate types.

We reported the wrong types when complaining that an aggregate's
moving-aggregate implementation is inconsistent with its regular
implementation.

This was wrong since the feature was introduced, so back-patch
to all supported branches.

Jeff Janes

Discussion: https://postgr.es/m/CAMkU=1x808LH=LPhZp9mNSP0Xd1xDqEd+XeGcvEe48dfE6xV=A@mail.gmail.com

src/backend/catalog/pg_aggregate.c

@@ -565,8 +565,8 @@ AggregateCreate(const char *aggName,
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 					 errmsg("moving-aggregate implementation returns type %s, but plain implementation returns type %s",
-							format_type_be(aggmTransType),
-							format_type_be(aggTransType))));
+							format_type_be(rettype),
+							format_type_be(finaltype))));
 	}
 
 	/* handle sortop, if supplied */