fix: legacy plugin doc

Author: twlite

packages/legacy/README.md

@@ -10,7 +10,7 @@ npm install @commandkit/legacy
 
 ## Usage
 
-This package provides a commandkit plugin that automatically registers the cache provider with the commandkit instance.
+This package provides a commandkit plugin that enables legacy command handler.
 
 ```js
 import { legacy } from '@commandkit/legacy';