Allow folding lists

[NoamDev]

Feature Request

Motivation

A section in a list, (numbered or not), contains everything that's in the right indent level below it, just like python blocks.

It would allow, for example, folding all levels, to reduce clutter, or navigate more easily.

+ Entry 1

  ...
   content
  ...
+ Entry 2

   ...
   content2
   ...

Since this content can be very long, it'd be useful if we can fold it, like we fold blocks in a programming language.

Description

Allow folding of list entries, like a programming languages's blocks.

Examples/Questions

In this example we can fold the #proof[...] block, and the math block. I want to be able to also fold the numbered list entries.

It should probably leave the first line as is, just like you'd leave the if ...: but fold the block underneath in python.