Update contribute to doc link (#251)

docs/conf.py

@@ -82,3 +82,5 @@ html_static_path = ["_static"]
 html_css_files = [
     "css/custom.css",
 ]
+
+notfound_urls_prefix = None

docs/index.md

@@ -61,5 +61,5 @@ environments/index
 
 Github <https://github.com/Farama-Foundation/MiniGrid>
 Donate <https://farama.org/donations>
-Contribute to the Docs <404>
+Contribute to the Docs <https://github.com/Farama-Foundation/MiniGrid/blob/master/.github/PULL_REQUEST_TEMPLATE.md>
 ```