docs: add link to "Using Plugins" from Plugins section (#7793)

Author: sapphi-red

docs/plugins/index.md

@@ -4,6 +4,8 @@
 Vite aims to provide out-of-the-box support for common web development patterns. Before searching for a Vite or Compatible Rollup plugin, check out the [Features Guide](../guide/features.md). A lot of the cases where a plugin would be needed in a Rollup project are already covered in Vite.
 :::
 
+Check out [Using Plugins](../guide/using-plugins) for information on how to use plugins.
+
 ## Official Plugins
 
 ### [@vitejs/plugin-vue](https://github.com/vitejs/vite/tree/main/packages/plugin-vue)