Rename 2020/ferguson1/cannibalism.log{,.md}

Rename cannibalism.log to cannibalism.log.md as an experiment. I
believe it'll look nicer this way. I also made some changes that should
make it easier to see where each part of the game is (in some cases for
the tail; every case for the head and insect).

Updated gameplay.md to refer to the renamed file and removed the now
irrelevant information about cannibalism.log.

I did not regenerate gameplay.html but I did not remove it either. The
reason I didn't is because there will be a tool that converts markdown
to html files and since this commit won't sync to the IOCCC website it's
not a risk in the meantime. Nevertheless I want the html file in for the
time being. The html file is still referenced in the file too because
it's preferable that it's used when everything goes live (except on
GitHub of course).

2020/ferguson1/gameplay.md

@@ -391,16 +391,9 @@ left go right etc.) and then after some length (but before you get beyond the
 snake) turn (so that you go perpendicular) and then watch as the snake starts
 unwinding at one place and then suddenly unwinds another direction.
 
-An example of extreme cannibalism is in the [cannibalism.log][] file. It has
-more than one run the first of one has several dumps. I didn't move for a long
-time: the initial size was 1500 and I would have won before moving if I went
-after bugs right away. In the last two captures of the first invocation (the
-third and second to last dump) the bug, head and tail of the snake are at:
-
-	     Bug: line 87, col 47
-	    Head: line 88, col 62; and line 115, col 48
-	    Tail: line 84, col 46; and line 112, col 29
-
+An example of extreme cannibalism is in the [cannibalism.log.md][] file. It
+explains information about the file including how to find the bug, head and tail
+of the snake, at least where it was documented. The first run has several dumps.
 The final example has the snake inside itself.
 
 # <a name="shedding" href="#toc">Gameplay: Shedding (stretching)</a>
@@ -814,7 +807,7 @@ years ago but I know it's true now. **Believe in yourself. Always.**
 [snake-colours]: snake-colours
 [number of hertz (flashes) per second triggering seizures]: https://www.epilepsysociety.org.uk/photosensitive-epilepsy#.Xjgpwi2ZOgQ
 [termcaps.c]: termcaps.c
-[cannibalism.log]: cannibalism.log
+[cannibalism.log.md]: cannibalism.log.md
 [crazy.log]: crazy.log
 [play.sh]: play.sh