fix(docs): add missing ts script type to getting started example (#1971)

Update getting-started.md

In the example `SpecialEdge.vue`  file (TS), we missed the TypeScript language descriptor in the second script section.

docs/src/guide/getting-started.md

@@ -436,7 +436,7 @@ const props = defineProps<EdgeProps>()
 const path = computed(() => getBezierPath(props))
 </script>
 
-<script>
+<script lang="ts">
 export default {
   inheritAttrs: false,
 }