A failed command printed the whole usage text after its error, burying
it. The root command's PersistentPreRunE now turns usage off once cobra
has checked the arguments and flags, so an error from running the
command is printed once on its own. Wrong arity, an unknown flag, a bad
flag value and a missing required flag still get usage; cobra checks
required flags after that hook, so the hook checks them first. Root
SilenceUsage was not used: in this cobra version it hides usage for
argument and flag errors too. Cobra still prints the error; Entry is
unchanged.
Model: opus-5-5
