Update the bhyve(8) manual to reflect that it is no
longer considered 'experimental.'

Reviewed by:	grehan
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271711 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f