scsi: documentation: Clean up scsi_mid_low_api.rst

 - Update the format (txt to rst) and location of this document
   (archive.org to docs.kernel.org)

 - Change url to URL

 - Spell out "lk" (Linux Kernel)

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240408025425.18778-2-rdunlap@infradead.org


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>