Add comment that pg_dump 'append' format is used only by pg_dump, per

Dave Page.

src/bin/pg_dump/pg_dump.c

@@ -12,7 +12,7 @@
  *	by PostgreSQL
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.463 2007/03/22 20:18:49 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.464 2007/03/22 20:47:12 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -478,7 +478,7 @@ main(int argc, char **argv)
 	/* open the output file */
 	if (pg_strcasecmp(format, "a") == 0 || pg_strcasecmp(format, "append") == 0)
 	{
-		/* not documented */
+		/* This is used by pg_dumpall, and is not documented */
 		plainText = 1;
 		g_fout = CreateArchive(filename, archNull, 0, archModeAppend);
 	}