in src/barChart.ts [631:640]
private createHelpLinkElement(): Element {
let linkElement = document.createElement("a");
linkElement.textContent = "?";
linkElement.setAttribute("title", "Open documentation");
linkElement.setAttribute("class", "helpLink");
linkElement.addEventListener("click", () => {
this.host.launchUrl("https://microsoft.github.io/PowerBI-visuals/tutorials/building-bar-chart/adding-url-launcher-element-to-the-bar-chart/");
});
return linkElement;
};