Cleanup: use braces in headers

intern/cycles/blender/id_map.h

intern/cycles/blender/util.h

intern/cycles/kernel/bvh/traversal.h

intern/cycles/kernel/closure/alloc.h

intern/cycles/kernel/closure/bsdf_toon.h

intern/cycles/kernel/device/oneapi/image.h

intern/cycles/kernel/geom/motion_triangle.h

intern/cycles/kernel/geom/patch.h

intern/cycles/kernel/integrator/intersect_closest.h

intern/cycles/kernel/integrator/shade_volume.h

intern/cycles/kernel/integrator/surface_shader.h

intern/cycles/kernel/light/area.h

intern/cycles/kernel/light/triangle.h

intern/cycles/kernel/osl/closures_setup.h

intern/cycles/kernel/osl/services_gpu.h

intern/cycles/kernel/osl/shaders/node_color.h

intern/cycles/kernel/osl/shaders/node_color_blend.h

intern/cycles/kernel/osl/shaders/node_fresnel.h

intern/cycles/kernel/osl/shaders/node_noise.h

intern/cycles/kernel/osl/shaders/node_ramp_util.h