vm_page_alloc.9: Adjust for the removal of PG_BUSY.

Clean up some manual pages (mainly .Dv related).

start adding .Mt to email addresses in man pages

This covers share/man/man[1579]. It also consolidates multiple lines
into one, removes spurious double quotes in names or emails,
and changes punctua

start adding .Mt to email addresses in man pages

This covers share/man/man[1579]. It also consolidates multiple lines
into one, removes spurious double quotes in names or emails,
and changes punctuation where appropriate. The target style is:
.An Name Aq Mt name@somewhere.tdl

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Import vm_page_alloc manpage from FreeBSD and add DFly-specifics.