Refactor @reawaitable decorator (#2029)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

returns/primitives/reawaitable.py

@@ -1,8 +1,10 @@
 from collections.abc import Awaitable, Callable, Generator
-from typing import NewType, TypeVar, cast, final
+from functools import wraps
+from typing import NewType, ParamSpec, TypeVar, cast, final
 
 _ValueType = TypeVar('_ValueType')
-_FunctionCoroType = TypeVar('_FunctionCoroType', bound=Callable[..., Awaitable])
+_AwaitableT = TypeVar('_AwaitableT', bound=Awaitable)
+_Ps = ParamSpec('_Ps')
 
 _Sentinel = NewType('_Sentinel', object)
 _sentinel: _Sentinel = cast(_Sentinel, object())
@@ -104,7 +106,9 @@ async def _awaitable(self) -> _ValueType:
         return self._cache  # type: ignore
 
 
-def reawaitable(coro: _FunctionCoroType) -> _FunctionCoroType:
+def reawaitable(
+    coro: Callable[_Ps, _AwaitableT],
+) -> Callable[_Ps, _AwaitableT]:
     """
     Allows to decorate coroutine functions to be awaitable multiple times.
 
@@ -124,6 +128,12 @@ def reawaitable(coro: _FunctionCoroType) -> _FunctionCoroType:
       >>> assert anyio.run(main) == 3
 
     """
-    return lambda *args, **kwargs: ReAwaitable(  # type: ignore
-        coro(*args, **kwargs),
-    )
+
+    @wraps(coro)
+    def decorator(
+        *args: _Ps.args,
+        **kwargs: _Ps.kwargs,
+    ) -> _AwaitableT:
+        return ReAwaitable(coro(*args, **kwargs))  # type: ignore[return-value]
+
+    return decorator