docs: improve with examples

docs/components/content/examples/DatePickerExample.vue

@@ -0,0 +1,16 @@
+<script setup>
+const date = ref(new Date())
+
+const label = computed(() => date.value.toLocaleDateString('en-us', { weekday: 'long', year: 'numeric', month: 'short', day: 'numeric' })
+)
+</script>
+
+<template>
+  <UPopover :popper="{ placement: 'bottom-start' }">
+    <UButton icon="i-heroicons-calendar-days-20-solid" :label="label" />
+
+    <template #panel="{ close }">
+      <DatePicker v-model="date" @close="close" />
+    </template>
+  </UPopover>
+</template>