fix crash on empty file

[Graveflo]

Basically, if you CTRL+A -> Backspace it can crash the lang server. contentChanges[0] expecting there to be at least one character seems to be the culprit. I also re-arranged the imports, but feel free to reject that change. Also, there was a . missing but apparently that doesn't matter.

edit: The changes in the config were steered by me trying to get Kate's settings to transfer. Not sure if I'm doing that right, but that is what I needed to do to get it work.