Special reducers don't preserve user-defined names

[RReverser]

As per recent API revamp proposal, special reducers attached to init/client_connected/client_disconnected events should preserve user-provided names and use the V9 moduledef out-of-band signal to indicate the lifecycle event it's attached to.

I'm working on the C# counterpart of this (V8 -> V9 migration), but I noticed that Rust implementation of the bindings macro, which already supports V9 moduledef, doesn't preserve the reducer names either.

cc @gefjon