Returning reference to temporaries.
GCC 13 added the feature to warn about dangling reference. It looks like there are several places that we are returning reference to temporary. For example:
https://gitlab.kitware.com/vtk/vtk-m/-/blob/master/vtkm/cont/CellSetExplicit.hxx#L408-L410.
Why did we tell it to return a reference rather by value?