Recognize buffer protocol special methods (#19581)

The special methods `__buffer__` and `__release_buffer__` were [added in
Python
3.12](https://docs.python.org/3/reference/datamodel.html#emulating-buffer-types).
Both are [implemented with slot
descriptors](https://docs.python.org/3/c-api/typeobj.html#:~:text=__buffer__),
and so should be treated as being implicitly positional-only like other
slot special methods.

Author: brianschubert

mypy/sharedparse.py

@@ -10,6 +10,7 @@
     "__call__",
     "__complex__",
     "__contains__",
+    "__buffer__",
     "__del__",
     "__delattr__",
     "__delitem__",
@@ -31,6 +32,7 @@
     "__new__",
     "__oct__",
     "__pos__",
+    "__release_buffer__",
     "__repr__",
     "__reversed__",
     "__setattr__",