Fix typo in comment.

Peter Geoghegan

Author: hlinnaka

src/backend/storage/lmgr/lock.c

@@ -3772,7 +3772,7 @@ lock_twophase_recover(TransactionId xid, uint16 info,
 
 /*
  * Re-acquire a lock belonging to a transaction that was prepared, when
- * when starting up into hot standby mode.
+ * starting up into hot standby mode.
  */
 void
 lock_twophase_standby_recover(TransactionId xid, uint16 info,