add xyz to local development serve with hot-reloading (#70)

Author: vspkulkarni

fern/docs/pages/welcome.mdx

@@ -52,7 +52,7 @@ npm install -g fern-api
 
 <Step title="Preview locally">
 
-Start a local development server with hot-reloading:
+Start a local development server with hot-reloading: xyz
 
 ```bash
 fern docs dev