Built-in array viewer for Set

[fonsp]

For AbstractArray, AbstractDict, tuples, and more, we use Pluto's built-in interactive tree viewer:

We should also use it for Set:

[vladflore]

Hey @fonsp ,

I'd like to have a go at this (I've already worked a bit on it and managed to get some results) :).

P.S. beginner here, Julia, Pluto and OS contributing so please bear with me :)

Best,
Vlad