* `edit.draw(state, fg, hide_cursor)` -- call this from `on.draw` to display
  the current editor state on the app window as requested in the call to
  `edit.initialize_state` that created `state`. `fg` is the color for
  foreground text (`Text_color` is a good default). Set `hide_cursor` to stop
  showing a blinking cursor (usually because you want a `readonly` editor; see
  below).
* `edit.draw(state, fg, hide_cursor, show_line_numbers)` -- call this from
  `on.draw` to display the current editor state on the app window as requested
  in the call to `edit.initialize_state` that created `state`. `fg` is the
  color for foreground text (`Text_color` is a good default). Set
  `hide_cursor` to stop showing a blinking cursor (usually because you want a
  `readonly` editor; see below), and `show_line_numbers` to render line
  numbers to the left of the editor.