Add missing apostrophe.

Masahiko Sawada

Discussion: http://postgr.es/m/CAD21AoAzaR_XV7j7Wk9-QYXaFoT8H4egKwXvFY63wc8Lw2C9cg@mail.gmail.com

src/backend/replication/logical/reorderbuffer.c

@@ -1252,7 +1252,7 @@ ReorderBufferCopySnap(ReorderBuffer *rb, Snapshot orig_snap,
 
 	/*
 	 * snap->subxip contains all txids that belong to our transaction which we
-	 * need to check via cmin/cmax. Thats why we store the toplevel
+	 * need to check via cmin/cmax. That's why we store the toplevel
 	 * transaction in there as well.
 	 */
 	snap->subxip = snap->xip + snap->xcnt;