Remove write modes from importlib.resources.abc.Traversable (#11124)

Author: pganssle

stdlib/importlib/abc.pyi

@@ -138,10 +138,10 @@ if sys.version_info >= (3, 9):
         # which is not the case.
         @overload
         @abstractmethod
-        def open(self, __mode: Literal["r", "w"] = "r", *, encoding: str | None = None, errors: str | None = None) -> IO[str]: ...
+        def open(self, __mode: Literal["r"] = "r", *, encoding: str | None = None, errors: str | None = None) -> IO[str]: ...
         @overload
         @abstractmethod
-        def open(self, __mode: Literal["rb", "wb"]) -> IO[bytes]: ...
+        def open(self, __mode: Literal["rb"]) -> IO[bytes]: ...
         @property
         @abstractmethod
         def name(self) -> str: ...