Fix unittest.TextTestResult.printErrorList() (#7341)

stdlib/unittest/runner.pyi

@@ -1,7 +1,7 @@
 import unittest.case
 import unittest.result
 import unittest.suite
-from typing import Callable, TextIO
+from typing import Callable, Iterable, TextIO
 
 _ResultClassType = Callable[[TextIO, bool, int], unittest.result.TestResult]
 
@@ -15,7 +15,7 @@ class TextTestResult(unittest.result.TestResult):
     def __init__(self, stream: TextIO, descriptions: bool, verbosity: int) -> None: ...
     def getDescription(self, test: unittest.case.TestCase) -> str: ...
     def printErrors(self) -> None: ...
-    def printErrorList(self, flavour: str, errors: tuple[unittest.case.TestCase, str]) -> None: ...
+    def printErrorList(self, flavour: str, errors: Iterable[tuple[unittest.case.TestCase, str]]) -> None: ...
 
 class TextTestRunner:
     resultclass: _ResultClassType