I deprecated Money::SYMBOLS, Money::SEPARATORS and Money::DELIMITERS when I created Money::Currency in #4.
One major release passed after it (Money 3), I think we can consider to bump set the deprecation target to Money 3.2 (as set for the Bank class).
I'm attaching a patch for this. I'm also refactoring the small Deprecation "framework" so that we can use it elsewhere in Money. For instance, I need it in #14.
Here's the patch (along with 2 other commits).
Looks good, I've merged your changes into trunk.