docs: Fix generation of manpage certbot(1).
docs: Fix generation of manpage certbot(1).

* docs/man/certbot.rst: Fix path to resource file.

lmcro/letsencrypt,jtl999/certbot,lmcro/letsencrypt,jsha/letsencrypt,letsencrypt/letsencrypt,bsmr-misc-forks/letsencrypt,letsencrypt/letsencrypt,jsha/letsencrypt,stweil/letsencrypt,stweil/letsencrypt,bsmr-misc-forks/letsencrypt,jtl999/certbot