Update __init__.pyi

Author: henryiii

src/boost_histogram/_core/axis/__init__.pyi

@@ -26,9 +26,9 @@ class _BaseAxis:
     @property
     def traits_ordered(self) -> bool: ...
     @property
-    def metadata(self) -> Any: ...
-    @metadata.setter
-    def metadata(self, item: Any) -> None: ...
+    def raw_metadata(self) -> Any: ...
+    @raw_metadata.setter
+    def raw_metadata(self, item: Any) -> None: ...
     @property
     def size(self) -> int: ...
     @property