Please omit "[FLAGS]" and "[ARGS]" from usage if not applicable

[joshtriplett]

The automatically generated usage message includes placeholders for "[FLAGS]" and "[ARGS]", even when every flag or arg is already shown directly in the usage message. For instance, for the example in #533 (comment) , the usage string looks like this:

USAGE:
    rebase [FLAGS] <onto|--interactive> [ARGS]

However, this command doesn't take any flags other than --interactive (and --help), and doesn't take any args other than onto. So ideally the usage message should look like:

USAGE:
    rebase <onto|--interactive>

[kbknapp]

It's detecting --help or --version for "flags" but what I could do is omit the [FLAGS] if the only non-required args are --help or --version as I agree...it's not super useful to keep the flags tag there just for those two.

[joshtriplett]

That sounds reasonable.

[ARGS] similarly shouldn't appear if all the arguments are required or otherwise part of a group that already displays them.

[kbknapp]

There was a recent commit that removes [ARGS] when it's only a single arg (required or not), but it currently doesn't do any determination as to whether or not all args are required, which makes sense to me so that's do-able.

[kbknapp]

This is now implemented in a local branch. Pushing the PR shortly.