I know it isn't a good thing to have many copy-and-pasted contents
(set file descriptions etc) in all MD files, but it's much more annoying
to maintain a bunch of .if \n [${MACHINE}] conditionals for all ports
and maintainers rarely notice that they also have to prepare or update
MD contents in MI content file with messy ifdefs.
XXX: of course common text should be shared by mdoc macro etc.
but I doubt playing mdoc(7) is really worth...
from common/xfer with messy mdoc .if conditionals
into MD xfer files so that developers can see
what contents are missing or obsolete and should be
written or updated
- remove some useless MD description for maintainability
XXX: still a bunch of unmaintained .if \n [${MACHINE}] in common files
