treemanifest: subclass the new `repository.imanifestdict` Protocol class
I missed this in 6412dcec52d3 somehow.
This is the same transformation as 3a90a6fd710d did for dirstate, but the
CamelCase naming was already cleaned up here. See 4ef6dbc27a99 for the benefits
of explicit subclassing.
--- a/mercurial/manifest.py Tue Dec 17 19:29:08 2024 -0500
+++ b/mercurial/manifest.py Tue Dec 17 19:32:31 2024 -0500
@@ -850,7 +850,7 @@
_noop = lambda s: None
-class treemanifest: # (repository.imanifestdict)
+class treemanifest(repository.imanifestdict):
_dir: bytes
_dirs: Dict[bytes, treemanifest]
_dirty: bool