Fix simple warning

src/language/MeshModule.cpp

@@ -6,8 +6,6 @@
 #include <GmshReader.hpp>
 #include <Mesh.hpp>
 
-class IMesh;
-
 template <>
 inline ASTNodeDataType ast_node_data_type_from<std::shared_ptr<IMesh>> = {ASTNodeDataType::type_id_t, "mesh"};