Allow markdown comments to match blocks that contain extra docs on first line

Fixes #66297

Implement List & new Tree drag and drop

fixes #66226

debug start actions disable when there is already a debug session running and we do not have any launch configuration selected

fixes #66047

Fixes #18131

* Switch to use more state machine like state management in progressService

**Problem**
In progress service, the `ProgressState` object is quite difficult to understand. Only a subset of fields are active at a given time so the state is really more like a state machine.

When enabling strict null checks, the existing pattern is also a pain because it is not clear which subset of fields go to gether and will not be undefined

**Fix**
I've been experimenting with writing states much explicitly. This has two main points:

- Encapsulating all state in a single state object (which the progress service already does)
- Encoding each valid state very explicitly in a state machine like manner

For progress service, the encoding breaks the `ProgressState` object up into five different states that the progress service transitions between.

* Use const enum and namespace

* Don't allow passing `infinite=false` to progressService

This state is currently unused and make no sense. Update the signature to  prevent ever trying to go into this state

This state is currently unused and make no sense. Update the signature to  prevent ever trying to go into this state