Feature: Fold headings and lists

[affvalente]

Ability to fold/collapse headings and lists, like in Obsidian.md where every heading and list is collapsible (just by secting a heading or having a second level list)

Very useful for outlining and structuring ideas, and a much lighter concept than the current 'collapsible' Lexical block

[affvalente]

An example: https://i.imgur.com/o6XvSQx.png

[zurfyx]

Thanks for the suggestion! This is a pretty opinionated feature, I wonder if other people would love to see it in the playground too. For now, you can grab some inspiration from the CollapsiblePlugin https://github.com/facebook/lexical/blob/table-types/packages/lexical-playground/src/plugins/CollapsiblePlugin/index.ts