src/vs/workbench/api/common/extHostDiagnostics.ts/DiagnosticCollection/clear
class DiagnosticCollection:	clear(): void {
		this._checkDisposed();
		this.#onDidChangeDiagnostics.fire([...this.#data.keys()]);
		this.#data.clear();
		this.#proxy?.$clear(this._owner);
	}