Preview does not show footnotes

**Describe the bug**
Preview does not show footnotes.

**To Reproduce**
Steps to reproduce the behavior:

1. Start writing a new issue
2. Write the following text (taken from reference).
```
Here is a simple footnote[^1].

A footnote can also have multiple lines[^2].

You can also use words, to fit your writing style more closely[^note].

[^1]: My reference.
[^2]: Every new line should be prefixed with 2 spaces.
This allows you to have a footnote with multiple lines.
[^note]:
Named footnotes will still render with numbers instead of the text but allow easier identification and linking.
This footnote also has been made with a different syntax using 4 spaces for new lines.
```
3. Click preview.
4. Footnotes are not rendered properly.

**Expected behavior**
Footnotes are rendered properly.

**Screenshots**

**Desktop (please complete the following information):**

- OS: Windows 10
- Browser: Chrome
- Browser Version: Version 106.0.5249.103 (Official Build) (64-bit)

**Additional context**
Reference: https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet#footnotes

Start by reproducing the issue in the issue preview using the provided footnote examples, then trace the preview rendering entry point in the TypeScript application. Compare the rendered output with the expected numbered and multi-line footnotes; done means all three supplied footnote forms render correctly in preview.

Written by the indexing model from the issue text.