Nginx custom rewrites documentation points to broken links

[bserem]

This line https://github.com/omega8cc/boa/blob/0960f23318d1a76aeb746d50ae5dc73419dc827d/docs/HINTS.txt#L23 points to broken links.

The nginx_modern_include exists no more. https://github.com/omega8cc/boa/blob/master/aegir/conf/nginx_compact_include.conf exists however.