Misc comment typo fixes.

Backpatch the applicable parts, just to make backpatching future patches
easier.

Author: hlinnaka

src/backend/lib/binaryheap.c

@@ -1,7 +1,7 @@
 /*-------------------------------------------------------------------------
  *
  * binaryheap.c
- *	  A simple binary heap implementaion
+ *	  A simple binary heap implementation
  *
  * Portions Copyright (c) 2012-2014, PostgreSQL Global Development Group
  *

src/backend/replication/walsender.c

@@ -938,7 +938,7 @@ StartLogicalReplication(StartReplicationCmd *cmd)
 
 	/*
 	 * Force a disconnect, so that the decoding code doesn't need to care
-	 * about a eventual switch from running in recovery, to running in a
+	 * about an eventual switch from running in recovery, to running in a
 	 * normal environment. Client code is expected to handle reconnects.
 	 */
 	if (am_cascading_walsender && !RecoveryInProgress())