doc: workaround for ugly API docs for overloaded functions with new Sphinx

New Sphinx added support for overloads and always displays them all with
full type annotations etc. This regresses the API reference for
overloaded functions like `fixture()`, `warns()`, `raises()` and friends
to become impossible to read.

I tried various workarounds but none worked except this one.

src/_pytest/python_api.py

@@ -12,7 +12,6 @@ from typing import Generic
 from typing import List
 from typing import Mapping
 from typing import Optional
-from typing import overload
 from typing import Pattern
 from typing import Sequence
 from typing import Tuple
@@ -28,6 +27,7 @@ if TYPE_CHECKING:
 import _pytest._code
 from _pytest.compat import final
 from _pytest.compat import STRING_TYPES
+from _pytest.compat import overload
 from _pytest.outcomes import fail
 
 
@@ -786,7 +786,7 @@ def raises(
 
 
 @overload
-def raises(
+def raises(  # noqa: F811
     expected_exception: Union[Type[E], Tuple[Type[E], ...]],
     func: Callable[..., Any],
     *args: Any,
@@ -795,7 +795,7 @@ def raises(
     ...
 
 
-def raises(
+def raises(  # noqa: F811
     expected_exception: Union[Type[E], Tuple[Type[E], ...]], *args: Any, **kwargs: Any
 ) -> Union["RaisesContext[E]", _pytest._code.ExceptionInfo[E]]:
     r"""Assert that a code block/function call raises an exception.