Print TypeId as hex for debugging

In <rust-lang#127134>, the `Debug` impl for
`TypeId` was changed to print a single integer rather than a tuple.
Change this again to print as hex for more concise and consistent
formatting, as was suggested.

Result:

    TypeId(0x1378bb1c0a0202683eb65e7c11f2e4d7)

core/src/any.rs

@@ -673,7 +673,7 @@ impl hash::Hash for TypeId {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Debug for TypeId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        f.debug_tuple("TypeId").field(&self.as_u128()).finish()
+        write!(f, "TypeId({:#034x})", self.as_u128())
     }
 }