[PL] RichardsFlow. Fix ogs_file_param/stubs.

Documentation/ProjectFile/process/RICHARDS_FLOW/c_RICHARDS_FLOW.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_intrinsic_permeability.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_mass_lumping.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_porosity.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_specific_body_force.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_storage.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_viscosity.md

+\ogs_missing_documentation

Documentation/ProjectFile/process/RICHARDS_FLOW/t_water_density.md

+\ogs_missing_documentation

ProcessLib/RichardsFlow/CreateRichardsFlowProcess.cpp

@@ -85,7 +85,7 @@ std::unique_ptr<Process> createRichardsFlowProcess(
     // Specific body force parameter.
     auto& specific_body_force = findParameter<double>(
         config,
-        //! \ogs_file_param_special{process__RICHARDS_FLOW_specific_body_force}
+        //! \ogs_file_param_special{process__RICHARDS_FLOW__specific_body_force}
         "specific_body_force", parameters, mesh.getDimension());
     DBUG("Use \'%s\' as specific body force parameter.",
          specific_body_force.name.c_str());
@@ -97,6 +97,7 @@ std::unique_ptr<Process> createRichardsFlowProcess(
         MathLib::toVector(specific_body_force(0, SpatialPosition{})).norm() > 0;
 
     // has mass lumping
+    //! \ogs_file_param{process__RICHARDS_FLOW__mass_lumping}
     auto mass_lump = config.getConfigParameter<bool>("mass_lumping");
 
     RichardsFlowProcessData process_data{intrinsic_permeability,