Add MusicWheel:GetCurrentSections()

[RhythmLunatic]

Necessary for using a custom group select along with the built in music select since SONGMAN:GetSongGroupNames() does not have any concept of the currently used sort.

Also needed to get the number of groups in the group select when the sort is not default.

[quietly-turning]

Thanks for working on this!

What differentiates a Section in the MusicWheel from a Current Section?

[RhythmLunatic]

I suppose there is no difference, but in my head current sort = currently generated sections.
I will change it to GetSections() instead since there is no "current sections" in the rest of the code, whatever sections exist are the current ones.

[quietly-turning]

Ah, okay, that makes more sense. Thanks for clarifying.

I don't think you need to change anything. I might include more description as part of my ongoing mess in #1997 eventually.

[quietly-turning]

Following recent convention, I'll leave this open for 24 hours to see if there is feedback from anyone else. Assuming there's no opposition, I'll merge tomorrow.

[RhythmLunatic]

In that case I will leave the function name as-is.