Add support for linting warnings from godot-gdscript-toolkit

[snorreks]

I'm submitting a...

• Bug report.
• Feature request.

Feature request

It would be great to see the linting warnings for godot-gdscript-toolkit gdlint directly in the editor. I have seen it work in neovim and vscode. This uses the same project as the request in #18.

[gerep]

Doesn't it show to you?

If I hover over the line, it shows the details.

Although I have godot-gdscript-toolkit gdlint installed, it works without it. That's an LSP functionality if I'm not mistaken.