[Bug] Toggling the markdown preview from the settings view leaves the state of the respective editor button unchanged

[bkis]

To Reproduce

1. Open settings
2. Toggle markdown preview
3. Close settings
4. Now the icon on the markdown preview button at the bottom of the editor is in the "wrong state", so it shows the wrong icon.

Expected behavior
The icon on this button should cycle from "eye" (turn md preview on) to "edit" (turn editor on) and back no matter where the markdown preview gets toggled (from settings or editor toggle button).

Actual behavior
See above ("To Reproduce").

This is a small cosmetic bug that doesn't break functionality, but it sure harms the UX.

[MasterKali06]

#561 will fix this.