Fix contributing links to point to local docs pages instead of GitHub

Author: puleeno

en/index.html

@@ -479,7 +479,7 @@ <h2>Feature Availability</h2>
                 </table>
 
                 <h2>Contributing</h2>
-                <p>We welcome contributions! Please read our <a href="https://github.com/jankx/jankx-lite/blob/main/CONTRIBUTING.md">Contributing Guide</a> for details.</p>
+                <p>We welcome contributions! Please read our <a href="./contributing/">Contributing Guide</a> for details.</p>
 
                 <hr>
                 <p style="text-align: center; color: var(--text-muted);">

vi/index.html

@@ -395,7 +395,7 @@ <h2>Khả Dụng Tính Năng</h2>
                 </table>
 
                 <h2>Đóng Góp</h2>
-                <p>Chúng tôi chào đón đóng góp! Vui lòng đọc <a href="https://github.com/jankx/jankx-lite/blob/main/CONTRIBUTING.md">Hướng Dẫn Đóng Góp</a>.</p>
+                <p>Chúng tôi chào đón đóng góp! Vui lòng đọc <a href="./contributing/">Hướng Dẫn Đóng Góp</a>.</p>
 
                 <hr>
                 <p style="text-align: center; color: var(--text-muted);">