src/vs/workbench/services/preferences/common/preferencesModels.ts/SettingsContentBuilder/pushGroup
class SettingsContentBuilder:	pushGroup(settingsGroups: ISettingsGroup): void {
		this._contentByLines.push('{');
		this._contentByLines.push('');
		this._contentByLines.push('');
		const lastSetting = this._pushGroup(settingsGroups, '  ');

		if (lastSetting) {
			// Strip the comma from the last setting
			const lineIdx = lastSetting.range.endLineNumber - this._rangeOffset;
			const content = this._contentByLines[lineIdx - 2];
			this._contentByLines[lineIdx - 2] = content.substring(0, content.length - 1);
		}

		this._contentByLines.push('}');
	}