Improve "find implementation" for macros.

[lerno]

In this case:

<*
 Seed the random with some best effort entropy.

 @require is_random(random)
*>
macro void seed_entropy(random)
{
	random.set_seed(&&entropy());
}

Trying to find the definition of set_seed (or usages thereof) should show all the methods set_seed since in this case there is no type on random. In a much later stage, one could apply the @require to validate the possible randoms, but that isn't necessary until WAY in the future.