docs(form): specify component ref type (nuxt#2296)

docs/content/2.components/form.md

@@ -117,23 +117,28 @@ You can manually set errors after form submission if required. To do this, simpl
 
 ```vue
 <script setup lang="ts">
-import type { FormError, FormSubmitEvent } from '#ui/types'
+import type { Form, FormSubmitEvent } from '#ui/types'
 
-const state = reactive({
+interface Schema {
+  email?: string
+  password?: string
+}
+
+const state = reactive<Schema>({
   email: undefined,
   password: undefined
 })
 
-const form = ref()
+const form = ref<Form<Schema>>()
 
-async function onSubmit (event: FormSubmitEvent<any>) {
-  form.value.clear()
+async function onSubmit (event: FormSubmitEvent<Schema>) {
+  form.value!.clear()
   try {
     const response = await $fetch('...')
     // ...
   } catch (err) {
     if (err.statusCode === 422) {
-      form.value.setErrors(err.data.errors.map((err) => ({
+      form.value!.setErrors(err.data.errors.map((err) => ({
         // Map validation errors to { path: string, message: string }
         message: err.message,
         path: err.path,