Live preview

[StevenBennettPDX]

Describe your feature request
FSNotes currently has two modes -- edit and preview. You can open a second copy of a file in a new window and then toggle that second window to "preview" mode. Then you type your edits in the main window and in a few seconds the second window shows the preview.

It would be nice to have the preview window to be in the main FSNotes application screen as an additional column. Markdown preview (https://markdownlivepreview.com/) is an example of this behavior. The code is open sourced (https://github.com/tanabe/markdown-live-preview). Could that code be incorporated into FSNotes?

Additional context
Add any other related information here. macOS or iOS?

[gingerbeardman]

Related (make the styles in the editor more representative)

• Header font-weights previewed in edit mode #1764
• [REQ] Better markdown css styles #263