apply clang-format to all headers with some exceptions

src/pair_zbl_const.h

@@ -29,6 +29,6 @@ namespace PairZBLConstants {
   static constexpr double d2 = 0.40290;
   static constexpr double d3 = 0.94229;
   static constexpr double d4 = 3.19980;
-}
-}
+}    // namespace PairZBLConstants
+}    // namespace LAMMPS_NS
 #endif