lesson 8 quiz; prepare new sentence mini-quiz

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

@@ -106,9 +106,21 @@ const example = computed(() => {
 const MAX_VOC = 5;
 
 const { frontmatter } = useData();
-const vocabulary = frontmatter.value[fmKey] as Record<string, IVoc[]>;
 
-vCats.value = Object.keys(vocabulary);
+const vocabulary: Record<string, IVoc[]> = {};
+
+for (const fk of fmKey.split(/[, ]+/g)) {
+  for (const [k, vs] of Object.entries(
+    frontmatter.value[fk] as Record<string, IVoc[]>,
+  )) {
+    vocabulary[k] = [...(vocabulary[k] || []), ...vs];
+
+    if (!vCats.value.includes(k)) {
+      vCats.value = [...vCats.value, k];
+    }
+  }
+}
+
 vChosenCats.value = [...vCats.value];
 makeVList();