rename theme unit lessons

docs/.vitepress/theme/components/VocabQuiz.vue

@@ -583,6 +583,10 @@ onMounted(async () => {
 
 onBeforeUnmount(() => {
   document.addEventListener("click", onModalClickOutside);
+
+  if (loadingIntervalId) {
+    clearInterval(loadingIntervalId);
+  }
 });
 </script>