Fixes #25740

Allows ts server plugins to specify that they support additional languages, such as html. These supported languages are defined in the contributes section of the package.json:

```json
"contributes": {
    "typescriptServerPlugins": [
        {
            "name": "tslint-language-service",
            "languages": [ "html" ]
        }
    ]
}
```

This change allows the TS Plugin in VSCode to send the additional file types to the TypeScript server for processing by the plugin

* Use getDomNodePagePosition to position suggest docs

* Use css instead of setting width explicityl

* Simplifying adjustdocs

Fix #26011

- use em dash instead of en dash

Use Chromium's new system-ui font alias

[theme] remove editorOptions.theme