Display visible aliases on the next line when they'd significantly widen display

[joshtriplett]

Visible aliases for subcommands (from #522) can significantly widen the help display, and move subcommand descriptions far away from the subcommand name, making it harder to pair them up. For example:

    log                          Show the history of the patch series
    pull-request|request-pull    Generate a mail requesting a pull of the patch series

Please consider an alternate format that doesn't widen the display like this. For instance, indent a bit and put the aliases underneath the main subcommand name:

    log             Show the history of the patch series
    pull-request    Generate a mail requesting a pull of the patch series
      Alias: request-pull

Or with more than one alias:

    log             Show the history of the patch series
    pull-request    Generate a mail requesting a pull of the patch series
      Aliases: req, request-pull

[kbknapp]

Very true. What about formatting them as such:

    log             Show the history of the patch series
    pull-request    Generate a mail requesting a pull of the patch series [aliases: req, request-pull]

To my eye, the newline and extra indent looks off...but that's also subjective 😜

The other option I thought about was:

    log             Show the history of the patch series
    pull-request    Generate a mail requesting a pull of the patch series
    req             Alias for 'pull-request'
    request-pull    Alias for 'pull-request'

[joshtriplett]

@kbknapp
Either of those looks good to me.

[kbknapp]

This is fixed with #530

Edit: I went with the [aliases: one, two, three] method as it was the least refactoring and still looks good to my eye.