consistent formatting: replace "if( XXX ){" with "if (XXX) {"

src/KOKKOS/pair_reaxc_kokkos.cpp

src/USER-MANIFOLD/fix_manifoldforce.cpp

src/USER-MANIFOLD/fix_nve_manifold_rattle.cpp

src/USER-MANIFOLD/fix_nvt_manifold_rattle.cpp

src/USER-MANIFOLD/manifold_cylinder_dent.cpp

src/USER-MANIFOLD/manifold_gaussian_bump.cpp

src/USER-MANIFOLD/manifold_spine.cpp

src/USER-MANIFOLD/manifold_thylakoid.cpp

src/USER-MANIFOLD/manifold_thylakoid_shared.cpp

src/USER-MANIFOLD/manifold_torus.cpp

src/USER-OMP/reaxc_init_md_omp.cpp

src/USER-OMP/reaxc_valence_angles_omp.cpp

src/USER-REAXC/pair_reaxc.cpp

src/USER-REAXC/reaxc_allocate.cpp

src/USER-REAXC/reaxc_ffield.cpp

src/USER-REAXC/reaxc_init_md.cpp

src/USER-REAXC/reaxc_io_tools.cpp

src/USER-REAXC/reaxc_reset_tools.cpp

src/USER-REAXC/reaxc_valence_angles.cpp