g:markdown_folding is applied on yaml header

[avidseeker]

Problem

Yaml header is folded when "let g:markdown_folding = 1".

---
## title: MWE [4 lines]······························································

Steps to reproduce

Step 1: mwe.md

---
title: MWE
---

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod

Step 2

nvim -u <(echo "let g:markdown_folding = 1") mwe.md

Expected behavior

Screen rendered as

---
title: MWE
---

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod

moved from: neovim/neovim#31203

[tpope]

Haven't tried it, but I'm guessing the easy fix here would probably be to add folding for the frontmatter as well.