Reset builder when resetting the output

src/digicode.ts

@@ -8,6 +8,7 @@ const light = document.getElementById('light') as HTMLDivElement;
 const keypad = document.getElementById('keypad') as HTMLDivElement;
 
 function resetCode() {
+  builder = '';
   display.innerText = '_'.repeat(CODE.length);
   light.classList.remove('is-success', 'is-error');
 }