fix(types): TreeCursor node can be None

tree_sitter/__init__.pyi

@@ -185,7 +185,7 @@ class Tree:
 @final
 class TreeCursor:
     @property
-    def node(self) -> Node: ...
+    def node(self) -> Node | None: ...
     @property
     def field_id(self) -> int | None: ...
     @property