[bug-mailutils] man page indentation

[積丹尼 Dan Jacobson]

mail --help's indentation of the words "Common options" and "Global
debugging settings" looks much better than that of the man page which
slides them further to the right, etc.

              precede message by a list of addresses

       -u, --user=USER
              operate on USER's mailbox

              Common options

       --config-file=FILE, --rcfile=FILE
              load this configuration file

       --config-help
              show configuration file summary

       --config-lint, --rcfile-lint
              check configuration file syntax and exit

       --config-verbose, --rcfile-verbose
              verbosely log parsing of the configuration files

       --no-site-config, --no-site-rcfile
              do not load site configuration file

       --no-user-config, --no-user-rcfile
              do not load user configuration file

       --set=PARAM=VALUE
              set configuration parameter

       --show-config-options
              show compilation options

              Global debugging settings

       --debug-level=LEVEL
              set Mailutils debugging level

       --debug-line-info
              show source info with debugging messages

       -?, --help
              give this help list

       --usage
              give a short usage message

       -V, --version
              print program version