rephrase tagline

Author: devsnek

index.html

@@ -22,7 +22,7 @@
     <a id="github" href="https://github.com/engine262/engine262" aria-label="Fork me on GitHub"></a>
 
     <h1>engine262</h1>
-    <p>A self-hosted JavaScript engine for development and exploration.</p>
+    <p>A JavaScript engine written in JavaScript for development and exploration.</p>
 
     <main>
       <section id="input-section">