docs: 更新demo

Author: twp0217

docs/demo/event.md

@@ -1,5 +1,5 @@
 ---
-order: 1
+order: 9
 ---
 
 ## event

docs/demo/placement.md

@@ -0,0 +1,7 @@
+---
+order: 2
+---
+
+## placement
+
+<code src="../examples/placement.tsx" />

docs/examples/placement.tsx

@@ -0,0 +1,16 @@
+import React from 'react';
+import InlineEdit from '@twp0217/react-inline-edit';
+
+export default () => {
+  const [editValue, setEditValue] = React.useState<string>('');
+
+  return (
+    <InlineEdit
+      defaultValue={editValue}
+      placement="top"
+      readView={editValue || '请点击输入值'}
+      editView={<input placeholder="请输入值" />}
+      onConfirm={setEditValue}
+    />
+  );
+};