Fix some typos and some incorrectly duplicated words

Author: Justin Pryzby
Reviewed-by: David Rowley
Discussion: https://postgr.es/m/ZD3D1QxoccnN8A1V@telsasoft.com

src/backend/optimizer/path/allpaths.c

@@ -4051,7 +4051,7 @@ recurse_push_qual(Node *setOp, Query *topquery,
  *
  * extra_used_attrs can be passed as non-NULL to mark any columns (offset by
  * FirstLowInvalidHeapAttributeNumber) that we should not remove.  This
- * parameter is modifed by the function, so callers must make a copy if they
+ * parameter is modified by the function, so callers must make a copy if they
  * need to use the passed in Bitmapset after calling this function.
  *
  * To avoid affecting column numbering in the targetlist, we don't physically

src/backend/optimizer/util/plancat.c

@@ -436,7 +436,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 			 * the number-of-tuples estimate to equal the parent table; if it
 			 * is partial then we have to use the same methods as we would for
 			 * a table, except we can be sure that the index is not larger
-			 * than the table.  We must ignore partitioned indexes here as as
+			 * than the table.  We must ignore partitioned indexes here as
 			 * there are not physical indexes.
 			 */
 			if (indexRelation->rd_rel->relkind != RELKIND_PARTITIONED_INDEX)