Indentation of level 3+ headings in dev.to must be 3 spaces

[derlin]

I don't know why, but in dev.to the level 3+ heading in the TOC need to have one more space to be rendered properly. The following:

- [h1](#h1)
  * [h2](#h2)
    + [h3](#h3)

will give:

• h1
  • h2
  • h3

By adding a space before the + on heading 3, we get the proper behavior:

• h1
  • h2
    • h3