docs(slideover): update

docs/app/components/content/examples/slideover/SlideoverProgrammaticExample.vue

@@ -0,0 +1,20 @@
+<script setup lang="ts">
+import { LazySlideoverExample } from '#components'
+
+const count = ref(0)
+
+const slideover = useSlideover()
+
+function open() {
+  count.value++
+
+  slideover.open(LazySlideoverExample, {
+    title: 'Slideover',
+    count: count.value
+  })
+}
+</script>
+
+<template>
+  <UButton label="Open" color="gray" variant="subtle" @click="open" />
+</template>