Remove duplicated words in comments of pgstat.c and pgstat_internal.h

Author: Atsushi Torikoshi
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/d00ddbf29f9d09b3a471e64977560de1@oss.nttdata.com

src/backend/utils/activity/pgstat.c

@@ -32,9 +32,9 @@
  * backend-local hashtable (pgStatEntryRefHash) in front of the shared
  * hashtable, containing references (PgStat_EntryRef) to shared hashtable
  * entries. The shared hashtable only needs to be accessed when no prior
- * reference is found in the local hashtable. Besides pointing to the the
+ * reference is found in the local hashtable. Besides pointing to the
  * shared hashtable entry (PgStatShared_HashEntry) PgStat_EntryRef also
- * contains a pointer to the the shared statistics data, as a process-local
+ * contains a pointer to the shared statistics data, as a process-local
  * address, to reduce access costs.
  *
  * The names for structs stored in shared memory are prefixed with

src/include/utils/pgstat_internal.h

@@ -296,9 +296,9 @@ static const char *const slru_names[] = {
  * values in a copy of the stats data, which is protected by ->lock. See
  * pgstat_fetch_stat_(archiver|bgwriter|checkpointer) for the reader side.
  *
- * The only exception to that is the the stat_reset_timestamp in these
- * structs, which is protected by ->lock, because it has to be written by
- * another backend while resetting
+ * The only exception to that is the stat_reset_timestamp in these structs,
+ * which is protected by ->lock, because it has to be written by another
+ * backend while resetting.
  * ----------
  */