use ParamSpec for pytest.skip instead of __call__ Protocol attribute

This is a more canonical way of typing generic callbacks/decorators
 (see https://mypy.readthedocs.io/en/stable/protocols.html#callback-protocols)

This helps with potential issues/ambiguity with `__call__` semanics in
type checkers -- according to python spec, `__call__` needs to be present
on the class, rather than as an instance attribute to be considered callable.

This worked in mypy because it didn't handle the spec 100% correctly (in this case this has no negative consequences)

However, `ty` type checker is stricter/more correct about it and every `pytest.skip` usage results in:

`error[call-non-callable]: Object of type `_WithException[Unknown, <class 'Skipped'>]` is not callable`

For more context, see:
- astral-sh/ruff#17832 (comment)
- https://discuss.python.org/t/when-should-we-assume-callable-types-are-method-descriptors/92938

Testing:

Tested with running mypy against the following snippet:
```
import pytest
reveal_type(pytest.skip)
reveal_type(pytest.skip.Exception)
reveal_type(pytest.skip(reason="whatever"))
```

Before the change:

```
test_pytest_skip.py:2: note: Revealed type is "_pytest.outcomes._WithException[def (reason: builtins.str =, *, allow_module_level: builtins.bool =) -> Never, def (msg: Union[builtins.str, None] =, pytrace: builtins.bool =, allow_module_level: builtins.bool =, *, _use_item_location: builtins.bool =) -> _pytest.outcomes.Skipped]"
test_pytest_skip.py:3: note: Revealed type is "def (msg: Union[builtins.str, None] =, pytrace: builtins.bool =, allow_module_level: builtins.bool =, *, _use_item_location: builtins.bool =) -> _pytest.outcomes.Skipped"
test_pytest_skip.py:4: note: Revealed type is "Never"
```

After the change:
```
test_pytest_skip.py:2: note: Revealed type is "_pytest.outcomes._WithException[[reason: builtins.str =, *, allow_module_level: builtins.bool =], Never, def (msg: Union[builtins.str, None] =, pytrace: builtins.bool =, allow_module_level: builtins.bool =, *, _use_item_location: builtins.bool =) -> _pytest.outcomes.Skipped]"
test_pytest_skip.py:3: note: Revealed type is "def (msg: Union[builtins.str, None] =, pytrace: builtins.bool =, allow_module_level: builtins.bool =, *, _use_item_location: builtins.bool =) -> _pytest.outcomes.Skipped"
test_pytest_skip.py:4: note: Revealed type is "Never"
```

All types are matching and propagated correctly.

Author: karlicoss

AUTHORS

@@ -134,6 +134,7 @@ Deysha Rivera
 Dheeraj C K
 Dhiren Serai
 Diego Russo
+Dima Gerasimov
 Dmitry Dygalo
 Dmitry Pribysh
 Dominic Mortlock

src/_pytest/outcomes.py

@@ -11,6 +11,8 @@
 from typing import Protocol
 from typing import TypeVar
 
+from typing_extensions import ParamSpec
+
 from .warning_types import PytestDeprecationWarning
 
 
@@ -80,18 +82,22 @@ def __init__(
 # We need a callable protocol to add attributes, for discussion see
 # https://github.com/python/mypy/issues/2087.
 
-_F = TypeVar("_F", bound=Callable[..., object])
+_P = ParamSpec("_P")
+_R = TypeVar("_R", covariant=True)
 _ET = TypeVar("_ET", bound=type[BaseException])
 
 
-class _WithException(Protocol[_F, _ET]):
+class _WithException(Protocol[_P, _R, _ET]):
     Exception: _ET
-    __call__: _F
+
+    def __call__(self, *args: _P.args, **kwargs: _P.kwargs) -> _R: ...
 
 
-def _with_exception(exception_type: _ET) -> Callable[[_F], _WithException[_F, _ET]]:
-    def decorate(func: _F) -> _WithException[_F, _ET]:
-        func_with_exception = cast(_WithException[_F, _ET], func)
+def _with_exception(
+    exception_type: _ET,
+) -> Callable[[Callable[_P, _R]], _WithException[_P, _R, _ET]]:
+    def decorate(func: Callable[_P, _R]) -> _WithException[_P, _R, _ET]:
+        func_with_exception = cast(_WithException[_P, _R, _ET], func)
         func_with_exception.Exception = exception_type
         return func_with_exception