Incorrect <link rel="canonical" ...> in documentation

[maxnikulin]

HTML markup on documentation pages contains incorrect <link rel="canonical" ...> elements:

curl -s  'https://firewalld.org/documentation/' | grep 'link rel="canonical"'
  <link rel="canonical" href="/documentation/">
<link rel="canonical" href="firewalld.github.io/documentation/" />

1. There should be just one canonical link.
2. Second link is treated as relative to https://firewalld.org/documentation/, so https://firewalld.org/documentation/firewalld.github.io/documentation/ is certainly an error. Likely, having a dedicated domain, you do not want to consider github.io is the primary location.

Perhaps the theme used to generate documentation should be fixed to avoid github.io links.