shortuser should stop before the first space character.
Examples:
"Foo Bar <foo.bar AT example DOT com>" -> "foo.bar"
(instead of "foo.bar AT example DOT com>" as it was before.)
"Foo Bar" -> "Foo"
*** failed to import extension badext: invalid syntax (badext.py, line 1)hg help [COMMAND]show help for a command, extension, or list of commands