Added "Caddy server"'s handling of 404 errors.

docs/content/templates/404.md

@@ -51,4 +51,4 @@ Your 404.html file can be set to load automatically when a visitor enters a mist
 * _Apache_ - one way is to specify `ErrorDocument 404 /404.html` in an `.htaccess` file in the root of your site.
 * _Nginx_ - you might specify `error_page   404  =  /404.html;` in your `nginx.conf` file.
 * _Amazon AWS S3_ - when setting a bucket up for static web serving, you can specify the error file.
-
+* _Caddy Server_ - using `errors { 404 /404.html }`. [Details here](https://caddyserver.com/docs/errors)