Add explanation of "UNKOWN" server type in WHM header

As a System Administrator, I would like to have added an explanation of why the server type in the WHM header appears as "UNKNOWN" (rather than "CENTOS 7.9"), so that the System Administrator can diagnose the issue.

I had done a kernel update manually and then forgot to do a server reboot. For a day or two, upcp failed in the maintenance script. Upon login to WHM, I noticed "UNKOWN [server]" in the WHM header but could not recall what was supposed to be in place of "UNKOWN" (since I don't login to often). I then ran the cPanel maintenance script and it failed with regards to the rpm database. I don't recall all the subsequent steps I took, but I did reboot the server and also ran the cPanel script to fix rpm issues. The server is now running normally. The WHM header now is currently showing "CONTOS 7.9 [server]". I also ran upcp manually and it completed successfully.

Perhaps link the "UNKNOWN" to a cpanel.net documentation webpage that explains what it means and the possible causes to investigate.

Perhaps WHM could test if a reboot is required following a manual kernel update. In my case, there was no "Server needs to be rebooted" notice in the WHM header that I sometimes see.

Thanks.