FreeBSD docs fixes (#3011)

* Update freebsd.md

* Update sidebar.html

freebsd link in sidebar

Author: michal-at-travisci

_includes/sidebar.html

@@ -92,6 +92,7 @@ <h3>CI Environment Reference</h3>
         <li><a href="/user/reference/linux/">Ubuntu Linux CI Environment References</a></li>
         <li><a href="/user/reference/osx/">macOS CI Environment Reference</a></li>
         <li><a href="/user/reference/windows/">Windows CI Environment Reference</a></li>
+        <li><a href="/user/reference/freebsd/">FreeBSD CI Environment Reference</a></li>
         <li><a href="/user/multi-os/">Building on Multiple Operating Systems</a></li>
         <li><a href="/user/multi-cpu-architectures/">Building on Multiple CPU Architectures</a></li>
         <li><a href="/user/environment-variables/">Environment Variables</a></li>

user/reference/freebsd.md

@@ -118,4 +118,4 @@ Pre-install compilers and linkers:
 
 ## Docker
 
-Currently unsupported. See [FreeBSD wiki](https://wiki.freebsd.org/Docker) for more details and https://wiki.freebsd.org/ContainerOrchestration for more native solutions.
+Currently unsupported. See [FreeBSD wiki about Docker](https://wiki.freebsd.org/Docker) for more details and [FreeBSD wiki on Container Orchestration](https://wiki.freebsd.org/ContainerOrchestration) for more native solutions.