src/vs/workbench/contrib/notebook/browser/notebookEditorDecorations.ts/NotebookRefCountedStyleSheet/unref
class NotebookRefCountedStyleSheet:	public unref(): void {
		this._refCount--;
		if (this._refCount === 0) {
			this._styleSheet.parentNode?.removeChild(this._styleSheet);
			this.widget.removeEditorStyleSheets(this._key);
		}
	}