Tweak sanity checks

Marlin/src/HAL/HAL_AVR/inc/SanityCheck.h

  * Checks for FAST PWM
  */
 #if ENABLED(FAST_PWM_FAN) && (ENABLED(USE_OCR2A_AS_TOP) && defined(TCCR2))
-    #error "USE_OCR2A_AS_TOP does not apply to devices with a single output TIMER2"
+  #error "USE_OCR2A_AS_TOP does not apply to devices with a single output TIMER2"
 #endif
 
 /**

Marlin/src/HAL/HAL_SAMD51/inc/SanityCheck.h

 #endif
 
 #if ENABLED(SDIO_SUPPORT)
-  #error "SDIO_SUPPORT is not supported."
+  #error "SDIO_SUPPORT is not supported on SAMD51."
 #endif
 
 #if ENABLED(FAST_PWM_FAN)