-h vs --help (A.K.A help() vs long_help())
The -h flag is not the same as --help.
-h corresponds to Arg::help/App::about and requests short "summary" messages while --help corresponds to Arg::long_help/App::long_about and requests more detailed, descriptive messages.
It is entirely up to clap what happens if you used only one of
Arg::help/Arg::long_help, see clap's documentation for these methods.
As of clap v2.33, if only a short message (Arg::help) or only
a long (Arg::long_help) message is provided, clap will use it
for both -h and --help. The same logic applies to about/long_about.