src/vs/editor/contrib/parameterHints/browser/parameterHintsWidget.ts/ParameterHintsWidget/renderParameters
class ParameterHintsWidget:	private renderParameters(parent: HTMLElement, signature: languages.SignatureInformation, activeParameterIndex: number): void {
		const [start, end] = this.getParameterLabelOffsets(signature, activeParameterIndex);

		const beforeSpan = document.createElement('span');
		beforeSpan.textContent = signature.label.substring(0, start);

		const paramSpan = document.createElement('span');
		paramSpan.textContent = signature.label.substring(start, end);
		paramSpan.className = 'parameter active';

		const afterSpan = document.createElement('span');
		afterSpan.textContent = signature.label.substring(end);

		dom.append(parent, beforeSpan, paramSpan, afterSpan);
	}