[web] Fix a bug preventing to index buttons to work in the genre pages

web-src/src/components/IndexButtonList.vue

@@ -5,7 +5,7 @@
         v-for="index in indices"
         :key="index"
         class="button is-small"
-        :to="'#index_' + index"
+        :to="{ hash: `#index_${index}`, query: $route.query }"
         >{{ index }}</router-link
       >
     </nav>

web-src/src/templates/ContentWithHeading.vue

@@ -53,7 +53,7 @@ export default {
       return this.options_visible ? 'chevron-up' : 'chevron-down'
     },
     position() {
-      return { hash: this.options_visible ? '#top' : '#app' }
+      return { hash: this.options_visible ? '#top' : '#app', query: this.$route.query }
     }
   },
   mounted() {