docs(form): update (#2167)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

docs/app/components/content/examples/form/FormExampleBasic.vue

@@ -0,0 +1,37 @@
+<script setup lang="ts">
+import type { FormError, FormSubmitEvent } from '#ui/types'
+
+const state = reactive({
+  email: undefined,
+  password: undefined
+})
+
+const validate = (state: any): FormError[] => {
+  const errors = []
+  if (!state.email) errors.push({ name: 'email', message: 'Required' })
+  if (!state.password) errors.push({ name: 'password', message: 'Required' })
+  return errors
+}
+
+const toast = useToast()
+async function onSubmit(event: FormSubmitEvent<any>) {
+  toast.add({ title: 'Success', description: 'The form has been submitted.', color: 'green' })
+  console.log(event.data)
+}
+</script>
+
+<template>
+  <UForm :validate="validate" :state="state" class="space-y-4" @submit="onSubmit">
+    <UFormField label="Email" name="email">
+      <UInput v-model="state.email" />
+    </UFormField>
+
+    <UFormField label="Password" name="password">
+      <UInput v-model="state.password" type="password" />
+    </UFormField>
+
+    <UButton type="submit">
+      Submit
+    </UButton>
+  </UForm>
+</template>