Remove surplus trailing semicolon

Author: Richard Guo
Discussion: https://postgr.es/m/CAMbWs4-qjotfa7G=5PEOw4LDDDX58MmTwDdpdoU3Quse_BKv1Q@mail.gmail.com

src/backend/optimizer/plan/planner.c

@@ -1418,7 +1418,7 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
 		else if (parse->groupClause)
 		{
 			/* Preprocess regular GROUP BY clause, if any */
-			root->processed_groupClause = list_copy(parse->groupClause);;
+			root->processed_groupClause = list_copy(parse->groupClause);
 			/* Remove any redundant GROUP BY columns */
 			remove_useless_groupby_columns(root);
 		}