[BE]: Enable ruff SLOT checks (#146276)

This enables a check that which a class which only inherits from immutable classes like str, tuple, and NamedTuple, also defined `__slots__` so they don't allocate memory unnecessarily. This also ensure contributors think about how they define their classes with subclass NamedTuples and str, of which we have many in our codebase

Pull Request resolved: https://github.com/pytorch/pytorch/pull/146276
Approved by: https://github.com/aorenste

functorch/dim/reference.py

@@ -139,6 +139,8 @@ def seq(a, b):
 
 
 class isin:
+    __slots__ = ()
+
     def __contains__(self, item):
         for x in self:
             if seq(item, x):
@@ -153,11 +155,11 @@ class isin:
 
 
 class llist(isin, list):
-    pass
+    __slots__ = ()
 
 
 class ltuple(isin, tuple):
-    pass
+    __slots__ = ()
 
 
 empty_dict = {}