[wp-docs] First order of business - code tweak page

[Kaf Oseo]

Lorelle brought up a good point here:

http://wordpress.org/support/topic.php?id=24151

On principle I'm not suggesting we allow code hacks to be scattered through
the documentation, but perhaps a page, a code sandbox of sorts listing minor
modifications, wouldn't be out of order. Then at least we can reenforce some
protective steps, like backing up files, commenting changes, etc.

-Kaf