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.

2015/endoh3/README.md

@@ -38,7 +38,7 @@ More generally use:
 ```sh
 cc -o prog prog.c foo.c
 ./prog
-^C # if necessary, where ^C is ctrl-C, interrrupt
+^C	# if necessary, where ^C is ctrl-C, interrrupt
 ```
 
 to run `prog` as whatever foo.c is in the joke PDP-11 emulator.