This property is used by the FunctionBuilder at design-time to provide a link to a help topic describing the function.
The default implementation returns an empty string. In this case, the Designer will not show the Help link."
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2