pub fn print_verb_help(verb: &str) -> Option<&'static VerbHelp>Expand description
Print one verb’s help to stdout: summary line, blank line, then either
(none) for verbs without flags or one --flag per line under a
Flags: header.
Returns the verb’s VerbHelp if found, or None if no entry exists
(so the caller can print a distinct “unknown verb” message and choose
its exit code).