helpMessage function
Returns a usage information of the CLI wrapped around parser.usage
.
Implementation
String helpMessage(ArgParser parser) =>
'A simple livereload web development server powered by build_runner.\n'
'\n'
'Usage: pub run livereload [directory] [options]\n'
' (If [directory] is omitted, `web` will be used.)\n'
'\n'
'${parser.usage}\n'
'\n'
'For further customization, please consider using livereload library instead of this CLI.';