Automation scripting: fix comment / uncomment button consistency

In automation scripting:

• Select text
• Press the "comment" button
  => Text is commented
  => selection is kept
  => On the first line, comments are added outside of the selection zone

• Keep the selection
• Press the "uncomment" button
  => First line remains commented because comments are outside of the selection zone
  => Selection is lost

=> Comment / Uncomment buttons should be usable one after another (i.e. if I press uncomment right after comment, the same text should not be commented anymore) and provide a consistent experience about text selection (either unselect after pressing a button or not for both of them).