builtins: improve bytes handling (#9027)

Author: JelleZijlstra

stdlib/builtins.pyi

@@ -677,7 +677,7 @@ class bytes(ByteString):
     def __rmul__(self, __n: SupportsIndex) -> bytes: ...
     def __mod__(self, __value: Any) -> bytes: ...
     # Incompatible with Sequence.__contains__
-    def __contains__(self, __o: SupportsIndex | bytes) -> bool: ...  # type: ignore[override]
+    def __contains__(self, __o: SupportsIndex | ReadableBuffer) -> bool: ...  # type: ignore[override]
     def __eq__(self, __x: object) -> bool: ...
     def __ne__(self, __x: object) -> bool: ...
     def __lt__(self, __x: bytes) -> bool: ...
@@ -798,10 +798,10 @@ class bytearray(MutableSequence[int], ByteString):
     def __contains__(self, __o: SupportsIndex | ReadableBuffer) -> bool: ...  # type: ignore[override]
     def __eq__(self, __x: object) -> bool: ...
     def __ne__(self, __x: object) -> bool: ...
-    def __lt__(self, __x: bytes) -> bool: ...
-    def __le__(self, __x: bytes) -> bool: ...
-    def __gt__(self, __x: bytes) -> bool: ...
-    def __ge__(self, __x: bytes) -> bool: ...
+    def __lt__(self, __x: ReadableBuffer) -> bool: ...
+    def __le__(self, __x: ReadableBuffer) -> bool: ...
+    def __gt__(self, __x: ReadableBuffer) -> bool: ...
+    def __ge__(self, __x: ReadableBuffer) -> bool: ...
     def __alloc__(self) -> int: ...
 
 @final
@@ -821,7 +821,7 @@ class memoryview(Sequence[int]):
     @property
     def ndim(self) -> int: ...
     @property
-    def obj(self) -> bytes | bytearray: ...
+    def obj(self) -> ReadableBuffer: ...
     @property
     def c_contiguous(self) -> bool: ...
     @property