Hibernation-info

Adds a specific safety-check on entering the Hibernation part of the food meter and provided a quick hint as to the general idea.  Thanks for the merge-cleanup and the guidance, Kevin.  Much appreciated.

Attempted to add memorial notes for engorgement, actually entering hibernation, and successful exit; killed a successful hibernator who'd nailed a firefighter zed I'd spawned for the purpose (manual suicide: pyre) and just got the msglog and the killcount, though.  Not sure what I missed?