Deprecate all methods of bitmix, not just Uint

bitmix had been defined with methods for all of `Int32, Uint32, Int64, Uint64`, while hash only supports `Uint` in its second argument.  This adds the necessary deprecations for all those methods. Calling the non-machine-size method isn't optimal, but it returns the type that bitmix did.
Merge pull request #6944 from mbauman/bitmix-deprecations

Deprecate all methods of bitmix, not just Uint