Apply suggestions from code review

Author: graingert

src/trio/_core/_run.py

@@ -1773,7 +1773,7 @@ def current_root_task(self) -> Task | None:
     # Core task handling primitives
     ################
 
-    @_public  # Type-ignore due to use of Any here.
+    @_public
     def reschedule(
         self,
         task: Task,

src/trio/_core/_tests/test_ki.py

@@ -540,7 +540,7 @@ def _identity(v: _T) -> _T:
         "https://github.com/python-trio/trio/pull/3110#discussion_r1802123644"
     ),
 )
-async def test_ki_does_not_leak_accross_different_calls_to_inner_functions() -> None:
+async def test_ki_does_not_leak_across_different_calls_to_inner_functions() -> None:
     assert not _core.currently_ki_protected()
 
     def factory(enabled: bool) -> Callable[[], bool]: