NGINX rules deviate from upstream defaults

[janmashat]

The comment where this change propagates states:

# Replica of regex from Drupals core .htaccess.

However I wasn't able to find a reference to these new file extensions at the source: https://git.drupalcode.org/project/drupal/-/blob/11.x/.htaccess

Now this has become a breaking change on our project where we serve legitimate .md files sitewide.