Fix `#[help]` to generate its variables without an extra underscore (#1587)
Fix `#[help]` to generate its variables without an extra underscore (#1587)

This changes the `#[help]` macro to generate its static variables without an
extra underscore. For instance, instead of `MY_HELP__OPTIONS`, it will generate
`MY_HELP_OPTIONS`.
acdenisSK/serenity,Flat/serenity