Core: Fix LaunchWebBrowser on macOS to handle addresses with dolar sign.

[klugier]

In TheIDE handling for these links doesn't work as expected:

menu.AddMenu("Online documentation..", IdeImg::Go_forward(), callback1(LaunchWebBrowser, "http://www.ultimatepp.org/www$uppweb$documentation$en-us.html"));
menu.AddMenu("Common information..", IdeImg::Go_forward(), callback1(LaunchWebBrowser, "http://www.ultimatepp.org/www$uppweb$community$en-us.html"));

The solution is to escape $ dolar signs.