message: Implement support for SPV_GOOGLE_user_type
  For debugging vulkan shaders generated by dxc
diff: @@ -250,6 +250,7 @@ void Reflector::CheckDebuggable(bool &debuggable, rdcstr &debugStatus) const
  "SPV_EXT_shader_atomic_float_add",
  "SPV_KHR_terminate_invocation",
  "SPV_EXT_shader_image_int64",
  + "SPV_GOOGLE_user_type",
  };
  // whitelist supported extensions
  