File encode win1252

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

- [X] This is a **enhancement/feature request**. Not a [bug or question](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 wanted feature/enhancement is not 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's settings are not touched. If your desired feature is present, you don't need to open this issue. The change will be part of the next Markor update.)

### Description

My files are copied between Windows and Android and are ansi encode.
Is it possible to set *.md files to this encoding?

### Information

Android version: 14
Device: S24ultra
App Version: 2.12.1

### Source

F-Droid

### Format / File type

Markdown

### Additional info / Log

```shell
-
```

Start by tracing how Markor opens and saves Markdown (*.md) files on Android, then find where file or editor encoding settings are exposed. The work is done when Markdown files can be read and written as Windows-1252 while the existing default encoding behavior remains unchanged.

Written by the indexing model from the issue text.