Fsnotes: Apply italic formatting using asterisks instead of underscores

[tewe]

Describe your feature request
The Format > Italic menu triggered by cmd+i surrounds selected text with underscores, which Markdown renders emphasised.

Personally I'd prefer it to use asterisks, which render the same.

This could be a preference.

[SoyunoForinfo]

+1 for this request.

Also I notice that in 4.3.3 using asterisks to write italics renders properly in the markdown preview but does not appear as italics in the edit mode:

Editor:

Preview: