src/vs/editor/contrib/parameterHints/browser/parameterHintsModel.ts/ParameterHintsModel/updateActiveSignature
class ParameterHintsModel:	private updateActiveSignature(activeSignature: number) {
		if (this.state.type !== ParameterHintState.Type.Active) {
			return;
		}

		this.state = new ParameterHintState.Active({ ...this.state.hints, activeSignature });
		this._onChangedHints.fire(this.state.hints);
	}