Corrected comment error in assembly-blink example (#337)

Author: Janidai

examples/assembly-blink/src/main.S

@@ -20,12 +20,12 @@ blink:
 delay_ms:
   ; Delay about (r25:r24)*ms. Clobbers r30, and r31.
   ; One millisecond is about 16000 cycles at 16MHz.
-  ; The inner loop takes 4 cycles, so we repeat it 3000 times
+  ; The inner loop takes 4 cycles, so we repeat it 4000 times
   ldi   r31, hi8(4000)
   ldi   r30, lo8(4000)
 1:
   sbiw    r30, 1
   brne    1b
   sbiw    r24, 1
   brne    delay_ms
-  ret
+  ret