Fix abi3 inheritance UI test

tests/ui/abi3_inheritance.stderr

@@ -1,24 +1,27 @@
-error[E0277]: the trait bound `PyException: PyClassBaseType` is not satisfied
+error[E0277]: pyclass `PyException` cannot be subclassed
  --> tests/ui/abi3_inheritance.rs:4:19
   |
 4 | #[pyclass(extends=PyException)]
-  |                   ^^^^^^^^^^^ the trait `PyClass` is not implemented for `PyException`, which is required by `PyException: PyClassBaseType`
+  |                   ^^^^^^^^^^^ required for `#[pyclass(extends=PyException)]`
   |
+  = help: the trait `PyClassBaseType` is not implemented for `PyException`
+  = note: if you own `PyException`, add `subclass` to the `#[pyclass]` macro: `#[pyclass(subclass)]`
   = note: with the `abi3` feature enabled, PyO3 does not support subclassing native types
   = help: the trait `PyClassBaseType` is implemented for `PyAny`
-  = note: required for `PyException` to implement `PyClassBaseType`
 note: required by a bound in `PyClassImpl::BaseType`
  --> src/impl_/pyclass.rs
   |
   |     type BaseType: PyTypeInfo + PyClassBaseType;
   |                                 ^^^^^^^^^^^^^^^ required by this bound in `PyClassImpl::BaseType`
 
-error[E0277]: the trait bound `PyException: PyClass` is not satisfied
+error[E0277]: pyclass `PyException` cannot be subclassed
  --> tests/ui/abi3_inheritance.rs:4:1
   |
 4 | #[pyclass(extends=PyException)]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `PyClass` is not implemented for `PyException`, which is required by `PyException: PyClassBaseType`
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required for `#[pyclass(extends=PyException)]`
   |
-  = help: the trait `PyClass` is implemented for `MyException`
-  = note: required for `PyException` to implement `PyClassBaseType`
+  = help: the trait `PyClassBaseType` is not implemented for `PyException`
+  = note: if you own `PyException`, add `subclass` to the `#[pyclass]` macro: `#[pyclass(subclass)]`
+  = note: with the `abi3` feature enabled, PyO3 does not support subclassing native types
+  = help: the trait `PyClassBaseType` is implemented for `PyAny`
   = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/abi3_nativetype_inheritance.stderr

@@ -1,26 +1,27 @@
-error[E0277]: the trait bound `PyDict: PyClassBaseType` is not satisfied
+error[E0277]: pyclass `PyDict` cannot be subclassed
  --> tests/ui/abi3_nativetype_inheritance.rs:5:19
   |
 5 | #[pyclass(extends=PyDict)]
-  |                   ^^^^^^ the trait `PyClass` is not implemented for `PyDict`, which is required by `PyDict: PyClassBaseType`
+  |                   ^^^^^^ required for `#[pyclass(extends=PyDict)]`
   |
+  = help: the trait `PyClassBaseType` is not implemented for `PyDict`
+  = note: if you own `PyDict`, add `subclass` to the `#[pyclass]` macro: `#[pyclass(subclass)]`
   = note: with the `abi3` feature enabled, PyO3 does not support subclassing native types
   = help: the trait `PyClassBaseType` is implemented for `PyAny`
-  = note: required for `PyDict` to implement `PyClassBaseType`
 note: required by a bound in `PyClassImpl::BaseType`
  --> src/impl_/pyclass.rs
   |
   |     type BaseType: PyTypeInfo + PyClassBaseType;
   |                                 ^^^^^^^^^^^^^^^ required by this bound in `PyClassImpl::BaseType`
 
-error[E0277]: the trait bound `PyDict: PyClass` is not satisfied
+error[E0277]: pyclass `PyDict` cannot be subclassed
  --> tests/ui/abi3_nativetype_inheritance.rs:5:1
   |
 5 | #[pyclass(extends=PyDict)]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `PyClass` is not implemented for `PyDict`, which is required by `PyDict: PyClassBaseType`
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^ required for `#[pyclass(extends=PyDict)]`
   |
-  = help: the following other types implement trait `PyClass`:
-            TestClass
-            pyo3::coroutine::Coroutine
-  = note: required for `PyDict` to implement `PyClassBaseType`
+  = help: the trait `PyClassBaseType` is not implemented for `PyDict`
+  = note: if you own `PyDict`, add `subclass` to the `#[pyclass]` macro: `#[pyclass(subclass)]`
+  = note: with the `abi3` feature enabled, PyO3 does not support subclassing native types
+  = help: the trait `PyClassBaseType` is implemented for `PyAny`
   = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)