Improve error message when a zone is not found

src/mesh/MeshCellZone.cpp

@@ -26,7 +26,17 @@ getMeshCellZone(const Mesh<Connectivity<Dimension>>& mesh, const IZoneDescriptor
   }
 
   std::ostringstream ost;
-  ost << "cannot find zone with name " << rang::fgB::red << zone_descriptor << rang::style::reset;
+  ost << "cannot find zone with name " << rang::fgB::red << zone_descriptor << rang::style::reset << '\n';
+  ost << "The mesh contains " << mesh.connectivity().template numberOfRefItemList<ItemType::cell>() << " zones: ";
+  for (size_t i_ref_cell_list = 0; i_ref_cell_list < mesh.connectivity().template numberOfRefItemList<ItemType::cell>();
+       ++i_ref_cell_list) {
+    const auto& ref_cell_list = mesh.connectivity().template refItemList<ItemType::cell>(i_ref_cell_list);
+    const RefId& ref          = ref_cell_list.refId();
+    if (i_ref_cell_list > 0) {
+      ost << ", ";
+    }
+    ost << rang::fgB::yellow << ref << rang::style::reset;
+  }
 
   throw NormalError(ost.str());
 }