docs(modal): update

docs/app/components/content/examples/modal/ModalFooterSlotExample.vue

@@ -0,0 +1,18 @@
+<script setup lang="ts">
+const open = ref(false)
+</script>
+
+<template>
+  <UModal v-model:open="open" title="Modal with footer" description="This is useful when you want a form in a Modal." :ui="{ footer: 'justify-end' }">
+    <UButton label="Open" color="gray" variant="subtle" />
+
+    <template #body>
+      <Placeholder class="h-48" />
+    </template>
+
+    <template #footer>
+      <UButton label="Cancel" color="gray" variant="outline" @click="open = false" />
+      <UButton label="Submit" color="gray" />
+    </template>
+  </UModal>
+</template>