convert to new .Dd format;

autoconf(4) cleanup:
- remove blatant lies (missing diagnostics, unconfigured devices never
detected even on pci or such busses...)
- .Tn UNIX -> .Ox
- xref boot_`arch`(8) rather than boot(8) when bo

autoconf(4) cleanup:
- remove blatant lies (missing diagnostics, unconfigured devices never
detected even on pci or such busses...)
- .Tn UNIX -> .Ox
- xref boot_`arch`(8) rather than boot(8) when boot(8) does not exist
- vague attempt to harmonize common texts

ok deraadt@

show more ...

s/doesn't/does not/

A start... need to wait on intro.4 until we have at least one supported
system =)