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.

2012/endoh1/README.md

@@ -32,7 +32,7 @@ this by default.
 
 
 
-### Alternate code:
+## Alternate code:
 
 An alternate version of this entry, `endoh1.alt.c`, is provided.
 This alternate code is a de-obfuscated version of `endoh1.c`.

2012/kang/README.md

@@ -34,7 +34,7 @@ echo "full spelling of an English cardinal numeral less than a quadrillion" | ./
 How does it have no `u` or `o` in a string in the source code and yet it gets
 `uno` right?
 
-### Alternate code:
+## Alternate code:
 
 This alternate code fixes the program that would throw off those who know German
 where the sound of 'V' is 'F' and so the program had the letter be 'F'. A

2012/konno/README.md

@@ -24,7 +24,7 @@ NOTE: N is an integer from 0 to 255.
 ./konno 30
 ```
 
-### Alternate code:
+## Alternate code:
 
 An alternate version of this entry, [konno.alt.c](konno.alt.c), is provided.
 This alternate code is an unobfuscated version of the winning code.

2012/vik/README.md

@@ -67,7 +67,7 @@ fire](https://en.wikipedia.org/wiki/Halt_and_Catch_Fire_(computing)) :-)
 ```
 
 
-### Alternate code:
+## Alternate code:
 
 For those few who might use Windows, To compile:
 

2012/zeitak/README.md

@@ -28,7 +28,7 @@ try [incorrect.c](incorrect.c) and the program itself.
 NOTE: it prints an error and exits on the first nesting error so it will not
 detect multiple issues!
 
-### Alternate code:
+## Alternate code:
 
 An alternate version of this entry, [zeitak.alt.c](zeitak.alt.c), is provided.
 The file [zeitak.alt.c](zeitak.alt.c) provides a version that has been slightly