doc: revise tagline (#6366)

pages/en/new-design/index.mdx

···
     <h1 className="special">Run JavaScript Everywhere</h1>
 
     Node.js® is a free, open-source, cross-platform JavaScript runtime
-    environment that lets developers write command line tools and server-side
-    scripts outside of a browser.
+    environment that lets developers create servers, web apps,
+    command line tools and scripts.
 
   </div>