Allow tuple of exceptions in ExceptionInfo.errisinstance

isinstance() accepts it and some code does pass a tuple.

Fixup for commit 55a570e.

Author: bluetech

src/_pytest/_code/code.py

@@ -520,7 +520,9 @@ def exconly(self, tryshort: bool = False) -> str:
                 text = text[len(self._striptext) :]
         return text
 
-    def errisinstance(self, exc: "Type[BaseException]") -> bool:
+    def errisinstance(
+        self, exc: Union["Type[BaseException]", Tuple["Type[BaseException]", ...]]
+    ) -> bool:
         """ return True if the exception is an instance of exc """
         return isinstance(self.value, exc)