cons-2.3dev 'cache-content' typo

[David Sanderson]

The cons-2.3dev documentation has an example that looks like this:

| $env = new cons(SIGNATURE => ['foo/*.o' => 'build',
|                               '*.o' => 'content',
|                               '*.a' => 'cache-content',
|                               '*' => 'content']);

I think the 'cache-content' should be 'stored-content'.