Various minor manpage fixes.

Various minor manpage fixes.

Signed-off-by: Steinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
  This mostly takes care of the difference between - and \-; in
  man pages, the former is hyphen (which indicates, among others,
  that a line might be split at that point), while the latter is a
  dash. For options, the latter is correct.

  There's also one minor grammatical fix.
Signed-off-by: Neil Brown <neilb@suse.de>