<a href="...">
and </a>
should include the full main package name."modelica://..."
<a href="modelica://Modelica.Mechanics.MultiBody.UsersGuide.Tutorial.LoopStructures.PlanarLoops"> Modelica.Mechanics.MultiBody.UsersGuide.Tutorial.LoopStructures.PlanarLoops</a>
appears as
Modelica.Mechanics.MultiBody.UsersGuide.Tutorial.LoopStructures.PlanarLoops<p> The feeder cables are connected to an <a href="modelica://Modelica.Electrical.Machines.BasicMachines.InductionMachines.IM_SquirrelCage"> induction machine</a>. </p>
appears as
The feeder cables are connected to an induction machine.