src/vs/platform/configuration/common/configurationModels.ts/ConfigurationModel/mergeContents
class ConfigurationModel:	private mergeContents(source: any, target: any): void {
		for (const key of Object.keys(target)) {
			if (key in source) {
				if (types.isObject(source[key]) && types.isObject(target[key])) {
					this.mergeContents(source[key], target[key]);
					continue;
				}
			}
			source[key] = objects.deepClone(target[key]);
		}
	}