Fix typos in comments

Author: alvherre

src/backend/access/transam/xlog.c

@@ -3115,7 +3115,7 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
  *
  * destsegno: identify segment to be created.
  *
- * srcTLI, srclog, srcseg: identify segment to be copied (could be from
+ * srcTLI, srcsegno: identify segment to be copied (could be from
  *		a different timeline)
  *
  * upto: how much of the source file to copy (the rest is filled with
@@ -7020,7 +7020,7 @@ StartupXLOG(void)
 	 * EndOfLogTLI is the TLI in the filename of the XLOG segment containing
 	 * the end-of-log. It could be different from the timeline that EndOfLog
 	 * nominally belongs to, if there was a timeline switch in that segment,
-	 * and we were reading the old wAL from a segment belonging to a higher
+	 * and we were reading the old WAL from a segment belonging to a higher
 	 * timeline.
 	 */
 	EndOfLogTLI = xlogreader->readPageTLI;