switch this header to 'pragma once' since I'm touching it already

Author: jepler

ports/espressif/common-hal/socketpool/Socket.h

@@ -24,8 +24,7 @@
  * THE SOFTWARE.
  */
 
-#ifndef MICROPY_INCLUDED_ESPRESSIF_COMMON_HAL_SOCKETPOOL_SOCKET_H
-#define MICROPY_INCLUDED_ESPRESSIF_COMMON_HAL_SOCKETPOOL_SOCKET_H
+#pragma once
 
 #include "py/obj.h"
 
@@ -49,5 +48,3 @@ typedef struct {
 } socketpool_socket_obj_t;
 
 void socket_user_reset(void);
-
-#endif // MICROPY_INCLUDED_ESPRESSIF_COMMON_HAL_SOCKETPOOL_SOCKET_H