use a specific type ignore for .__hash__ reassignment

Author: asottile

babi/highlight.py

@@ -27,9 +27,9 @@
 Captures = Tuple[Tuple[int, 'Rule'], ...]
 
 
-def uniquely_constructed(t: T) -> T:
+def uniquely_constructed(t: type[T]) -> type[T]:
     """avoid tuple.__hash__ for "singleton" constructed objects"""
-    t.__hash__ = object.__hash__  # type: ignore
+    t.__hash__ = object.__hash__  # type: ignore[method-assign]
     return t