Proposed Code / Reference: Support Hierarchical Category Legend

You can see my proposed code / reference on GitHub at https://github.com/afragen/the-events-calendar-category-colors/issues/83

I just wanted to make sure people looking for this sort of thing would be able to find it on the WP.org forum as well as on GitHub. I’m sure I’m not the only one that would like a color-coded category legend that is also hierarchical.