localrepo: drop the CamelCase name for `localrepo.revlognarrowfilestorage`

See 61557734c0ae for the reasoning.

mercurial/localrepo.py

@@ -1258,7 +1258,7 class revlogfilestorage: # (repository.
         return filelog.filelog(self.svfs, path, try_split=try_split)
 
 
-class RevlogNarrowFileStorage:
+class revlognarrowfilestorage:  # (repository.ilocalrepositoryfilestorage)
     """File storage when using revlogs and narrow files."""
 
     def file(self, path):
@@ -1274,15 +1274,6 class RevlogNarrowFileStorage:
         )
 
 
-revlognarrowfilestorage = interfaceutil.implementer(
-    repository.ilocalrepositoryfilestorage
-)(RevlogNarrowFileStorage)
-
-if typing.TYPE_CHECKING:
-    # Help pytype by hiding the interface stuff that confuses it.
-    revlognarrowfilestorage = RevlogNarrowFileStorage
-
-
 def makefilestorage(requirements, features, **kwargs):
     """Produce a type conforming to ``ilocalrepositoryfilestorage``."""
     features.add(repository.REPO_FEATURE_REVLOG_FILE_STORAGE)