cleanup winner README.md files

Fixed cases where there was a bad trailing backslash.

Improved a few cases where a code block was needed
to highlight some text.

Changed a few cases where a code block needed to
declared as, say, a sh code block.

Fixed a few cases where the winner information was not properly formatted.

Plus a few nits and clarifying text was added.

1989/jar.2/README.md

@@ -22,10 +22,8 @@ make all
 [enter some lisp]
 
 ./jar.2 < some_lisp_file
-
 ```
 
-
 NOTE: this entry will likely segfault on invalid input.
 
 
@@ -39,7 +37,6 @@ cat chocolate_cake.lisp ; ./jar.2 < chocolate_cake.lisp
 ./try.sh chocolate_cake.lisp
 
 ./try.sh try.txt
-
 ```