Handling of cells outside of viewport

[kieferrm]

Testing #223152

1. select two cells
2. scroll the lower cell (cell 2) out of the viewport
3. cmd+/
4. scroll cell 2 partially into the viewport -> only cell 1 has been commented
5. cmd+/ -> cell 1 has been uncommented, cell 2 has been commented

After step 3 I'd expect both cells to be commented and after step 5 both to be uncommented

[Yoyokrazy]

Need to move the toggle comments action off of the editor command. Case is simpler overall since we are not operating on cursors or a specific selection.

Relying on editor.executeCommands() is the limitation, as we don't have editors outside of the viewport. We can construct these edits in a similar way to a LineCommentCommand and simply apply them to the model, allowing us to apply to cells outside of the viewport