identify: restructure code to make it more readable

identify/help: say what the command does first, mention bookmarks

templatefilters: improve person() for john.doe@example.com BEFORE: person('john.doe@example.com') -> 'john' AFTER: person('john.doe@example.com') -> 'john doe'

help: do not show full help text for command on option errors Example $ hg clone --jump foo bar hg clone: option --jump not recognized hg clone [OPTION]... SOURCE [DEST] make a copy of an existing repository options: -U --noupdate the clone will include an empty working copy (only a repository) -u --updaterev REV revision, tag or branch to check out -r --rev REV [+] include the specified changeset -b --branch BRANCH [+] clone only the specified branch --pull use pull protocol to copy metadata --uncompressed use uncompressed transfer (fast over LAN) -e --ssh CMD specify ssh command to use --remotecmd CMD specify hg command to run on the remote side --insecure do not verify server certificate (ignoring web.cacerts config) [+] marked option can be specified multiple times use "hg help clone" to show the full help text Motivation for this change If the user already has specified the command, he probably already knows the command to some extent. Apparently, he has a problem with the options, so we show him just the synopsis with the short help and the details about the options, with a hint on the last line how to get the full help text. Why is Mercurial better with this change? Experts who just forgot about the details of an option don't get that much text thrown at them, while the newbies still get a hint on the last line how to get the full help text.