i18n-it: translate [OPTION]..., not [OPTIONS]...: keep the singular
Since [OPTION]... is intended to mean more options, it was translated in Italian
as plural. However the plural is conveyed by `...', so switch to the singular.
This was also useful because for the '-o OPT' extdiff option, I have to
translate `OPT' as a singular.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.