Add T to PhantomData impl Debug This add debug information for `PhantomData`, I believe it's make sense to add this to debug impl of `PhantomData` since `T` is what define what is the `PhantomData` just write `"PhantomData"` is not very useful for debugging. Alternative: * `PhantomData::<{}>` * `PhantomData { t: "str_type" }` `@rustbot` label +T-libs-api -T-libs