C comment: fix "the the" mentions in C comments

Reported-by: Christoph Dreis

Discussion: https://postgr.es/m/007e01d3519e$2734ca10$759e5e30$@freenet.de

Author: Christoph Dreis

Author: bmomjian

src/backend/optimizer/prep/prepunion.c

@@ -2502,7 +2502,7 @@ build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
  * 		Find AppendRelInfo structures for all relations specified by relids.
  *
  * The AppendRelInfos are returned in an array, which can be pfree'd by the
- * caller. *nappinfos is set to the the number of entries in the array.
+ * caller. *nappinfos is set to the number of entries in the array.
  */
 AppendRelInfo **
 find_appinfos_by_relids(PlannerInfo *root, Relids relids, int *nappinfos)

src/test/regress/expected/triggers.out

@@ -1934,7 +1934,7 @@ $$;
 --
 -- Verify behavior of statement triggers on partition hierarchy with
 -- transition tables.  Tuples should appear to each trigger in the
--- format of the the relation the trigger is attached to.
+-- format of the relation the trigger is attached to.
 --
 -- set up a partition hierarchy with some different TupleDescriptors
 create table parent (a text, b int) partition by list (a);

src/test/regress/sql/triggers.sql

@@ -1409,7 +1409,7 @@ $$;
 --
 -- Verify behavior of statement triggers on partition hierarchy with
 -- transition tables.  Tuples should appear to each trigger in the
--- format of the the relation the trigger is attached to.
+-- format of the relation the trigger is attached to.
 --
 
 -- set up a partition hierarchy with some different TupleDescriptors