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.

2000/thadgavin/README.md

@@ -1,8 +1,8 @@
 # Most Portable Output
 
 Thaddaeus Frogley\
-UK\
-\
+UK
+
 Gavin Buttimore\
 UK