scsi: docs: scsi-generic: Multiple cleanups

Make the heading be concise yet still descriptive.
This makes the subsystem table of contents more readable (IMO).

Spell "CDROM" as "CD-ROM".
Capitalize "Linux".

Use https instead of http for URLs.

Drop the Linux Documentation Project URL for the SCSI generic HOWTO
since it hasn't been updated since 2002. Use Doug Gilbert's URL
for it instead.

Drop some outdated documentation & references.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20230518212749.18266-8-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: Doug Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>