Fix typo

Author: petere

src/backend/access/transam/xlogprefetch.c

@@ -722,7 +722,7 @@ pg_stat_get_prefetch_recovery(PG_FUNCTION_ARGS)
 	if (!(rsinfo->allowedModes & SFRM_Materialize))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mod required, but it is not allowed in this context")));
+				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
 		elog(ERROR, "return type must be a row type");