Inconsistent behaviour with GitHub on escaped backslashes in maths environment

**Describe the bug**
When a double backslash is placed in a maths environment, the GitHub markdown render treats this as it would treat a normal, single backslash, whereas markdown-preview treats this as a newline.

This is a VERY niche inconsistency but it matters in my particular use-case because `mdformat` decides to escape all backslashes placed, including in maths environments. This can be fixed using `mdformat-myst` but that isn't yet published on NixOS so I can't use it (I'm attempting to get it packaged).

As issues go, this is about as low priority as they come.

**To Reproduce**
Steps to reproduce the behavior:
1. Place a double backslash in a maths equation in a markdown file
2. Open the preview
3. See that it is treated as a newline

**Expected behavior**
Follow GitHub's behaviour on this and treat it as a normal backslash in the maths environment.

**Desktop (please complete the following information):**
- OS: NixOS