HAL style tweak

Marlin/src/HAL/HAL_DUE/HAL_Due.h

@@ -166,13 +166,13 @@ void HAL_enable_AdcFreerun(void);
 #define HAL_IDLETASK 1
 #define HAL_INIT 1
 #ifdef __cplusplus
-extern "C" {
+  extern "C" {
 #endif
 void HAL_idletask(void);
 void HAL_init(void);
 char *dtostrf (double __val, signed char __width, unsigned char __prec, char *__s);
 #ifdef __cplusplus
-}
+  }
 #endif
 
 #endif // _HAL_DUE_H