mdoc: improvements to SEE ALSO.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@276293 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
mdoc: improvements to SEE ALSO.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@276294 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f