update code page

Author: mmcky

website/code.html

@@ -37,12 +37,12 @@ <h2 align="right"><a href="/">Back</a></h2>
                     <table class="alt" style="width:100%;">
                         <tbody>
                             <tr>
-                                <td>Julia Code</td>
-                                <td><a href="https://github.com/QuantEcon/book-dp1-public/code/jl/">Files on GitHub</a></td>
+                                <td>Julia</td>
+                                <td><a href="https://github.com/QuantEcon/book-dp1-public/tree/main/code/jl">Files on GitHub</a></td>
                             </tr>
                             <tr>
-                                <td>Python Code</td>
-                                <td><a href="https://github.com/QuantEcon/book-dp1-public/code/py/">Files on GitHub</a></td>
+                                <td>Python</td>
+                                <td><a href="https://github.com/QuantEcon/book-dp1-public/tree/main/code/py">Files on GitHub</a></td>
                             </tr>
                         </tbody>
                     </table>