Add subdiagnostic hint if async context manager is used in non-async `with` statement

[AlexWaygood]

CPython just added a really nice hint to its diagnostic message if you use an async context manager in a non-async with statement:

Python 3.14.0a7+ (heads/main:fac41f56d4b, May 25 2025, 12:27:36) [Clang 17.0.0 (clang-1700.0.13.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> class Foo:
...     async def __aenter__(self): ...
...     async def __aexit__(self, *args): ...
...     
>>> with Foo():
...     ...
...     
Traceback (most recent call last):
  File "<python-input-1>", line 1, in <module>
    with Foo():
         ~~~^^
TypeError: 'Foo' object does not support the context manager protocol (missed __exit__ method) but it supports the asynchronous context manager protocol. Did you mean to use 'async with'?

We should add a subdiagnostic to our equivalent error message that suggests using async with instead of with, so that it looks something like:

error: Object of type `Foo` cannot be used with `with` because it does not implement `__enter__` and `__exit__`
note: Objects of type `Foo` *can* be used as async context managers
note: Consider using `async with` here

(Here's a playground link to show our current error message: https://play.ty.dev/00fecd74-416e-46d1-8368-a2b87cbb84cd.)

[AlexWaygood]

@lipefree -- this should be fairly easy to do, if you're still looking for easy issues :-)

• Here's an example of an existing diagnostic where we add a subdiagnostic giving additional information: https://github.com/astral-sh/ruff/blob/83a036960b8e7d31856a5f10d208b9eac894a187/crates/ty_python_semantic/src/types/infer.rs#L5751-L5755
• The area of the code you'd need to edit is here: https://github.com/astral-sh/ruff/blob/83a036960b8e7d31856a5f10d208b9eac894a187/crates/ty_python_semantic/src/types.rs#L6099-L6104
• We'd only want to add the subdiagnostic if context_expression.try_call_dunder(db, "__aenter__", CallArgumentTypes::none()) and context_expression.try_call_dunder(db, "__aexit__", CallArgumentTypes::positional([Type::none(db), Type::none(db), Type::none(db)])) both return Ok() variants

[lipefree]

Hey @AlexWaygood ! I will try to look into it tonight then and see if I can come up with something !

[AlexWaygood]

(Tests should be added using mdtest snapshots to https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/with/sync.md)