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