Update custom-block-shape addon: Add superellipsed reporters

[mmmmaaaaarrrrrrkkkkkkkk]

This PR adds an option to the Customizable block shape addon, allowing you to enable superellipsed roundness on reporters.

Superellipsed roundness is really cool. It's what makes your iPhone icons feel very natural, as it prevents any sudden jumps in curvature on rounded rectangles.

The science behind it is really cool but I'll spare you the reading and show you this graphic:

On the left one (which does not use superellipsed rounding), the area where it has no comb means there is no curvature. The curvature comb literally jumps to 0 infinitely steeply, creating an unnatural edge.

If you know what a squircle is, you've seen some level of superellipse roundness. This addon essentially makes reporters look kind of like squircles.

The superellipse strength value can go from 50% (off) to 150% (max).

You can see the difference between values here:

OFF

70%

100% (default)

150%

To make the difference clearer, here's off, and max right below:

[JeremyGamer13]

personally i dont get why this is important but if people like it then i dont see why not
this is probably fine but maybe leave a note that higher values can be confused with other output types like square for array

[mmmmaaaaarrrrrrkkkkkkkk]

done!