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/arachnid/README.md

@@ -36,7 +36,7 @@ QWERTY keyboards.  Rogue players, vi users, and Dvorak typists are
 invited to get lost (or use the alt version)!
 
 
-### Alternate code:
+## Alternate code:
 
 To use:
 

2004/gavare/README.md

@@ -22,7 +22,7 @@ make
 ./gavare > ioccc_ray.ppm
 ```
 
-### Alternate code:
+## Alternate code:
 
 The author provided [on their web page for the
 entry](https://gavare.se/ioccc/ioccc_gavare.c.html) an unobfuscated version that was used

2004/hoyle/README.md

@@ -24,7 +24,7 @@ make
 ./hoyle 2 0 1 0 -0.001
 ```
 
-### Alternate code:
+## Alternate code:
 
 An alternate version of this entry, [hoyle.alt.c](hoyle.alt.c), is provided.
 This alternate code has a missing newline and used a non-standard tab stop size.

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: