Suppress tidy warning `modernize-use-equals-default`

We don't use `= default` in certain VTK-m based code as `nvcc` does not
allow it and produces the following warning:

"__deviceddd__/__host__ annotation is ignored on a function that is explicitly defaulted on its first declaration"

Accelerators/Vtkm/Filters/vtkmGradient.cxx

@@ -50,6 +50,8 @@ inline vtkm::cont::DataSet CopyDataSetStructure(const vtkm::cont::DataSet& ds)
 class MaskBits
 {
 public:
+  // We are not using `= default` here as nvcc does not allow it.
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   VTKM_EXEC_CONT MaskBits() {}
 
   explicit MaskBits(int mask)