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

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>