[2.0] Remove deprecation of delete hash[key] (and change its

[bearophile]

Jesse Phillips:
> I can't test it now, but I would think that hash.remove(key) would return 
> the removed value. Couldn't find mention in the docs but if it is true
> delete hash.remove(key);

In DMD 1.025 hash.remove(key) is a void.

Bye,
bearophile