Fix tmp/format-headers.sh, format headers

The script had "s surrounding the git ls-files command which turned it
to a single file which of course is wrong.

Ran script again fixing many README.md files that had incorrect number
of blank lines for critical headers.

This will have to be done a final but a good number of files have been
corrected.

1991/buzzard/README.md

@@ -26,6 +26,7 @@ bugs.md](/bugs.md#1991-buzzard).
 ./buzzard
 ```
 
+
 ## Alternate code:
 
 This version changes the keys `f` for forward, `l` for left and `r` for right by
@@ -58,7 +59,6 @@ You are invited to try to cheat, ... if you can figure out how!  :-)
 
 ## Author's remarks:
 
-
 ### How to play
 
 When the game starts, you are at the far end of the maze from the exit, looking