Godot DAP "Completions Request" from the DAP spec is not implemented

[van800]

Tested versions

Reproducible on master after https://github.com/godotengine/godot/pull/97585 is merged, because the ability to evaluate expressions in debugger was introduced.

System information

All OS

Issue description

"Completions Request" from the DAP spec is not implemented

Steps to reproduce

Start debugging with DAP in vscode. Stop on a brakepoint In the Watch area try to type self. and there would be no completion.

Minimal reproduction project (MRP)

Empty project with a scene and one gd script is enough.