Dollar sign inside backticks renders incorrectly when KaTex is disabled

### ⚠️ This issue respects the following points: ⚠️

- [x] This is a **bug**. Not a [question or feature request](https://github.com/gsantner/markor/issues/new/choose).
- [x] The topic is **not** already reported at [Issues](https://github.com/gsantner/markor/issues?q=#js-issues-search). _(I've searched it)_.
- [x] Markor **is** up to date. See [Releases](https://github.com/gsantner/markor/tags) for the latest version. Updates are available from [F-Droid](https://f-droid.org/en/packages/net.gsantner.markor/) and GitHub.
- [x] The bug is still present in the latest development version (git master). (Please [download](https://nightly.link/gsantner/markor/workflows/build-android-project/master) and try the test version of Markor, named **Marder**. Don't worry; Markor and Marder appear as completely separate applications. You can install both side-by-side, and Markor settings are not touched. In case the issue is resolved there, you don't need to create a bug report. The change will be part of the next Markor update.)

### Description

````
``` $ ``` or `` $ `` shows as \$ when rendering markdown
````

when KaTex is enabled it renders correctly

### Steps to reproduce

Disable KaTex

Just enter
````
``` $ ```
````
in a new file

### Information

Android version: 11
Device: Realme
App Version: latest

### Source

Google Play

### Format / File type

Markdown

### Additional info / Log

```shell
-
```

Reproduce the issue in Markor on Android by disabling KaTeX and entering ``` $ ``` in a new Markdown file. Compare the rendered output with KaTeX enabled; done means the dollar sign inside backticks renders literally in both configurations.

Written by the indexing model from the issue text.