message: docs: add vue imports in code examples
diff: @@ -30,6 +30,7 @@ The `route` object is a reactive object, so any of its properties can be watched
  ```js
  import { useRoute } from 'vue-router'
  +import { ref } from 'vue'
  export default {
  setup() {
  @@ -55,6 +56,7 @@ While you can still use in-component navigation guards with a `setup` function,
  ```js
  import { onBeforeRouteLeave, onBeforeRouteUpdate } from 'vue-router'
  +import { ref } from 'vue'
  export default {
  setup() {
  @@ -88,6 +90,7 @@ Vue Router exposes the internal behavior of RouterLink as a Composition API func
  ```js
  import { RouterLink, useLink } from 'vue-router'
  +import { computed } from 'vue'
  export default {
  name: 'AppLink',
  