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.

1998/schweikh1/README.md

@@ -30,7 +30,6 @@ if you don't have a Mac as it has some interesting details about the entry.
 
 ### Alternate build:
 
-
 ```sh
 make alt
 ```
@@ -40,6 +39,7 @@ make alt
 
 Use `schweikh1.alt` as you would `schweikh1` above.
 
+
 ### Alternate try:
 
 Bonus exercise: modify the code to provide a different compiler.