Feature Request

Please add markdown to the list of files supported when saving files.

Steps to Reproduce the Issue

1. Create a new file (Ctrl+N or File > New)
2. Type something
3. Save the file (Ctrl+S or File > Save)
4. Click on the Save as type: dropdown (or Alt+T)

Actual Behavior

No markdown option available.

Expected Behavior

There's a markdown option available.