Changing heading level of 'Alternate code'

Change level 3 (###) to level 2 (##):

    sgit -e 's/^### \(Alternate code\)/## \1/g' '*README.md'

which is the same as:

    sgit -e 's/^### Alternate code/## Alternate code/g' '*README.md'

This is per discussion in GitHub.

2004/kopczynski/README.md

@@ -42,7 +42,7 @@ What happens if you feed the program source to the program? Can you figure out
 why?
 
 
-### Alternate code:
+## Alternate code:
 
 The judges modified the program to print its result.  The original
 program returned the result as an exit code: