fix: add alt text to Built with Netlify badge (#5068)

* fix: add alt text to Built with Netlify badge

* Update docs/_includes/default.liquid

Co-authored-by: Pelle Wessman <pelle@kodfabrik.se>

---------

Co-authored-by: Pelle Wessman <pelle@kodfabrik.se>

Author: JoshuaKGoldberg

docs/_includes/default.liquid

@@ -130,7 +130,7 @@
         </ul>
         <div class="netlify-badge">
           <a href="https://www.netlify.com">
-            <img src="https://www.netlify.com/img/global/badges/netlify-color-accent.svg" loading="lazy">
+            <img src="https://www.netlify.com/img/global/badges/netlify-color-accent.svg" alt="Built with Netlify (Netlify logo)" loading="lazy">
           </a>
         </div>
       </div>