[FEATURE] editor: ensure empty last line on saving

[dnalor]

Describe the solution you'd like

it would be great if the editor could (optionally) ensure there's an empty last line when saving
example (featherpad):

Output from the debug section in the settings dialog

see #3251

[pbek]

Thank you for your feature request. Pull requests to look at welcome. 😉

[pbek]

26.6.5

• Added an optional editor setting to ensure that the note text ends with an
  empty last line when a note is stored (for #3255)