scsi: docs: scsi-changer: Shorten the chapter heading

Make the heading be concise yet still descriptive.
This makes the subsystem table of contents more readable (IMO).
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20230518212749.18266-5-rdunlap@infradead.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Gerd Knorr <kraxel@bytesex.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Documentation/scsi/scsi-changer.rst

 .. SPDX-License-Identifier: GPL-2.0
 
-========================================
-README for the SCSI media changer driver
-========================================
+=========================
+SCSI media changer driver
+=========================
 
 This is a driver for SCSI Medium Changer devices, which are listed
 with "Type: Medium Changer" in /proc/scsi/scsi.