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.

1985/sicherman/README.md

@@ -26,7 +26,7 @@ echo IOCCC | ./sicherman
 ./sicherman < sicherman.c | ./sicherman
 ```
 
-### Alternate code:
+## Alternate code:
 
 This alternate version, which is the original entry, requires either an old
 enough compiler or a compiler that supports `-traditional-cpp`. If you have such