bugfix: duplicate help command

[jakebolam]

Description

Before:

    set-default <version>     Sets the default fallback yarn version, if not supplied and no .yvmrc found
    get-default-version       Gets the default set yarn version
    version                   Outputs the version of yvm that is installed
    update-self               Updates yvm to the latest version
    help                      Show help text
    help [cmd]                display help for [cmd]

After:

    set-default <version>     Sets the default fallback yarn version, if not supplied and no .yvmrc found
    get-default-version       Gets the default set yarn version
    version                   Outputs the version of yvm that is installed
    update-self               Updates yvm to the latest version
    help                      Show help text

[brandonbaksh]

@jakebolam I guess we have "two" usages for the help command.

1. yvm

• This should output the list of commands (just like a help page)

2. yvm help

• This should do the same thing as 1)

I think with your changes it invalidates 2).

See the screenshot below:

Notice it says Invalid help command for yvm help

I think in general we want to be able to support both 1) and 2) and have them both display the exact same response.

Also the usage of yvm help [cmd] is pretty confusing. For example, doing something like yvm help list, I would expect to get some help docs on how the list command works. Instead I get the message Invalid help command since the 2nd argument is #FAKENEWS

[jakebolam]

@brandonbaksh that yvm help invalid command is a tricky one
as for the confusing output of help [cmd] this is recently coming from a new version fo commander.
Looking at there docs/github there is no current way to disabled it. May need to put a PR up on there side. (Added an issue: tj/commander.js#892)