This manual page seems to contain a hyphen where a minus sign was
intended. By default, "-" chars are interpreted as
hyphens (U+2010) by groff, not as minus signs (U+002D). Since
options to programs use minus signs (U+002D), this means for
example in UTF-8 locales that you cannot cut and paste options,
nor search for them easily. The Debian groff package currently
forces "-" to be interpreted as a minus sign due to the number of
manual pages with this problem, but this is a Debian-specific
modification and hopefully eventually can be removed.

"-" must be escaped ("\-") to be interpreted as minus. If you
really intend a hyphen (normally you don't), write it as "\(hy"
to emphasise that fact. See groff(7) and especially groff_char(7)
for details, and also the thread starting with
http://lists.debian.org/debian-devel/2003/debian-devel-200303/msg01481.html