Preserving empty lines preceding the archive

[everyonesdesign]

Reproduction

1. Open a document with some actual and archived items
2. Add new lines between actual and archived items
3. Run "Todo: Archive" action

Expected behaviour (behaviour of PlainTasks on ST3)

Empty lines between actual tasks and archived ones are still there

Actual behaviour

Empty lines are stripped, leaving no gaps between actual and archived tasks

More context

I'm a SublimeText + PlainTasks users, but now I decided to try out VSCode.

I found this extension as a tasks manager for VSCode and, I must say, amazing job. Very solid extension.

One difference I noticed is that on Sublime I could leave some empty space (new lines) between my actual tasks an archive, thus keeping the tasks below the fold of the screen (I'm not interesting in seeing these tasks). Archived items are also either completed or rejected, so they're very bright, and it really makes the archived items pop agains the active ones.

[fabiospampinato]

Sounds reasonable, PR welcome.