Rich Text Editor escapes valid Markdown

**Describe the bug**

The editor escapes valid markdown used in Jekyll. I have the following Markdown in Jekyll

*[MY]: My Abbr
[Link to my post]({% link _post/mypost.md %})

When toggling the Rich Text editor, I end up with the code escaped.

**To Reproduce**

See this diff saved after opening the .md file with the Rich text editor.

https://github.com/motionsplan/motionsplan-dk-jekyll/pull/52/files

Links and abbr. is escaped.

**Expected behavior**

Making sure that the abbr and links are left alone.

**Screenshots**

**Applicable Versions:**

- Netlify CMS version: [e.g. 2.10.16]
- Git provider: [GitHub] and Netlify
- OS: [e.g. Windows 7]
- Browser version [e.g. chrome 22, safari 11]

- Node.JS version:

**CMS configuration**

https://github.com/motionsplan/motionsplan-dk-jekyll/blob/master/admin/config.yml

**Additional context**