#1249 Fix Doxygen warnings.

Sources/ModelInstances/Elasticity/ElasticityModel.hpp

Sources/ModelInstances/Heat/HeatModel.hpp

Sources/ModelInstances/Laplacian/Model.hpp

Sources/ModelInstances/Stokes/Model.hpp

...es/PostProcessing/RefineMeshQuadranglesSpectral/Model.hpp

Sources/Test/Geometry/Coloring/Model.hpp

Sources/Test/Geometry/CoordsInParallel/Model.hpp

Sources/Test/Geometry/DomainListInCoords/Model.hpp

Sources/Test/Geometry/LightweightDomainList/Model.hpp

...ators/NonConformInterpolator/FromVertexMatching/Model.hpp

Sources/Test/Operators/P1_to_HigherOrder/Model.hpp