Replace $attrs with a prop

aleksis/apps/alsijil/frontend/components/documentation/Documentation.vue

@@ -8,7 +8,7 @@
     >
       <lesson-information
         class="flex-grow-1"
-        :documentation="$attrs.documentation"
+        :documentation="documentation"
       />
       <lesson-summary
         class="flex-grow-1"
@@ -20,7 +20,7 @@
         @loading="loading = $event"
         @save="$emit('close')"
       />
-      <lesson-notes class="flex-grow-1" :documentation="$attrs.documentation" />
+      <lesson-notes class="flex-grow-1" :documentation="documentation" />
     </div>
     <v-divider />
     <v-card-actions v-if="!('compact' in $attrs)">
@@ -57,6 +57,12 @@ export default {
       documentationsMutation: createOrUpdateDocumentations,
     };
   },
+  props: {
+    documentation: {
+      type: Object,
+      required: true,
+    },
+  },
   methods: {
     save() {
       this.$refs.summary.save();