Show `Annotated` in messages

```py
from typing import Annotated

def foo(a: Annotated[int, "huuh?"]) -> None: ...

reveal_type(foo) # Revealed type is "def (a: int Annotated with 'huuh?') -> None"
foo("") # error: Argument 1 to "foo" has incompatible type "str"; expected "int Annotated with 'huuh?'" [arg-type]
```

Start by reproducing the Annotated example in basedmypy and inspect the type-rendering and diagnostic paths that produce reveal_type and arg-type messages. Compare the current output with the wording shown in the issue; done means both messages display the Annotated metadata consistently.

Written by the indexing model from the issue text.