fix problematic HTML caused by certain trailing backslashes

In cases that are **outside of a markdown code block**,
a markdown line with ending in a tailing "\" can generate
problematic HTML.

We certain trailing backslashes outside of a markdown code block
with "<br>" HTML elements, or in some cases eliminated the
need for a trailing backslash.

In a few cases some unnecessary trailing backslashes inside
of a markdown code block were removed.

The following markdown files were changed in this commit:

```
1990/dds/README.md
1990/jaw/README.md
1991/ant/README.md
1991/rince/README.md
1991/westley/README.md
1992/vern/README.md
1992/westley/README.md
1998/schweikh1/README.md
2004/anonymous/README.md
2005/sykes/README.md
2006/toledo2/README.md
2011/toledo/README.md
2012/endoh2/README.md
2012/tromp/README.md
2013/robison/README.md
2015/hou/README.md
2015/howe/README.md
2015/schweikhardt/README.md
2018/burton1/README.md
2018/burton2/README.md
2018/ferguson/README.md
2018/vokes/README.md
2020/ferguson1/README.md
```

Performed `make www` to test these changes.

2020/ferguson1/README.md

@@ -28,48 +28,48 @@ and non-zero).
 
 ### Variables:
 
-* **WAIT**\
+* **WAIT**<br>
 	    	positive or negative integer that changes how long to wait for
 		a key press prior to moving again. < 0 blocks which allows
 		for complete control over movement at your own pace. Default
 		231; you can move faster by holding down or rapidly pressing an
 		arrow key.
 
-* **WALLS**\
+* **WALLS**<br>
 	        whether the walls are passable or impassable. Default passable,
 		1; 0 makes walls impassable where you die if you hit a wall.
 
-* **EVADE**\
+* **EVADE**<br>
 	        how many movements the Snake moves before the bug (well
 		insect; see notes below about why bugs) will move to
 		another location in the field. Default 300; 0 disables.
 
-* **SIZE**\
+* **SIZE**<br>
 	        initial size of the Snake. Note that it grows by one per
 		move so at the default 5 it will not initially be 5
 		characters long! < 0 is likely an immediate win.
 
-* **MAXSIZE**\
+* **MAXSIZE**<br>
 	        the maximum size the Snake can become before the game is
 		won. < 0 is the maximum size based on terminal dimensions;
 		any other size will be capped based on the terminal
 		dimensions to prevent problems. Note that when **SIZE+GROW >=
 		MAXSIZE** you win _before_ you grow to the full size!
 
-* **GROW**\
+* **GROW**<br>
 	        size to grow every time you eat a bug. Default 5; negative
 		values are allowed. 'Negativity' creates for fun gameplay modes with
 		enough creativity. See [gameplay.html](gameplay.html)
 		GitHub) as well as [play.sh](play.sh) for some examples.
 
-* **SHED**\
+* **SHED**<br>
 	        every **SHED** movements you will grow (> 0), shrink (< 0) or
 		stay the same length (0) by the **SHEDS** (below) value. Again
 		with creativity you can create some fun gameplay modes.  NOTE:
 		the concept of shedding in this game is a misnomer; see notes
 		below.
 
-* **SHEDS**\
+* **SHEDS**<br>
 	        every **SHED** movements will impact what this value means: grow
 		(> 0), shrink (< 0) or not at all (0). Exception: if the snake
 		eats a bug the counter isn't incremented. Again with creativity
@@ -80,7 +80,7 @@ and non-zero).
 		NOTE: the concept of shedding in this game is a misnomer; see
 		notes below.
 
-* **CANNIBAL**\
+* **CANNIBAL**<br>
 	        whether you can go through the Snake or not. Default is 0
 		(cannot - die if you try).
 
@@ -160,7 +160,7 @@ Here are some other features of the game:
 
 *   A drawing/practising mode (**WAIT** < 0 makes `timeout()` block).
 
-*   Computer plays the game (**WAIT=0**).\
+*   Computer plays the game (**WAIT=0**).<br>
 	- **EPILEPSY/STIMULATION OVERLOAD WARNING** included in the relevant
 	section (this goes for a low **EVADE** value too).