dm raid: bump target version, update comments and documentation

Bump target version to reflect the documented fixes are available.
Also fix some code comments (typos and clarity).

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Documentation/device-mapper/dm-raid.txt

@@ -348,3 +348,7 @@ Version History
 1.13.1  Fix deadlock caused by early md_stop_writes().  Also fix size an
 	state races.
 1.13.2  Fix raid redundancy validation and avoid keeping raid set frozen
+1.14.0  Fix reshape race on small devices.  Fix stripe adding reshape
+	deadlock/potential data corruption.  Update superblock when
+	specific devices are requested via rebuild.  Fix RAID leg
+	rebuild errors.