IOSS: Helper class to avoid fmt includes in public headers

packages/seacas/libraries/ioss/src/Ioss_use_fmt.h

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+// Copyright(C) 2024 National Technology & Engineering Solutions
+// of Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
+// NTESS, the U.S. Government retains certain rights in this software.
+//
+// See packages/seacas/LICENSE for details
+
+// This class should be included if you want to use the lib::fmt
+// output for any of the classes shown below:
+// * ZoneConnectivity
+// * Field
+// * BoundaryCondition
+
+#include <fmt/ostream.h>
+
+#if FMT_VERSION >= 90000
+#include "Ioss_Field.h"
+#include "Ioss_StructuredBlock.h"
+#include "Ioss_ZoneConnectivity.h"
+
+namespace fmt {
+  template <> struct formatter<Ioss::ZoneConnectivity> : ostream_formatter
+  {
+  };
+
+  template <> struct formatter<Ioss::Field> : ostream_formatter
+  {
+  };
+
+  template <> struct formatter<Ioss::BoundaryCondition> : ostream_formatter
+  {
+  };
+} // namespace fmt
+#endif