localrepo: subclass the new `ilocalrepositoryfilestorage` Protocol class

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.

Since there's only one method in this Protocol class and it needs to be
abstract because of the direct subclassing (see cdd4bc69bfc1), do that here.

hgext/sqlitestore.py

@@ -86,7 +86,6 from mercurial import (
 )
 from mercurial.interfaces import (
     repository,
-    util as interfaceutil,
 )
 from mercurial.utils import (
     hashutil,
@@ -1282,8 +1281,7 def newreporequirements(orig, ui, create
     return requirements
 
 
[e-mail](repository.ilocalrepositoryfilestorage)
-class sqlitefilestorage:
+class sqlitefilestorage(repository.ilocalrepositoryfilestorage):
     """Repository file storage backed by SQLite."""
 
     def file(self, path):

mercurial/interfaces/repository.py

@@ -1658,6 +1658,7 class ilocalrepositoryfilestorage(Protoc
     tracked file path.
     """
 
+    @abc.abstractmethod
     def file(self, f):
         """Obtain a filelog for a tracked path.
 

mercurial/localrepo.py

@@ -1241,7 +1241,7 def makemain(**kwargs):
     return localrepository
 
 
-class revlogfilestorage:  # (repository.ilocalrepositoryfilestorage)
+class revlogfilestorage(repository.ilocalrepositoryfilestorage):
     """File storage when using revlogs."""
 
     def file(self, path):
@@ -1256,7 +1256,7 class revlogfilestorage: # (repository.
         return filelog.filelog(self.svfs, path, try_split=try_split)
 
 
-class revlognarrowfilestorage:  # (repository.ilocalrepositoryfilestorage)
+class revlognarrowfilestorage(repository.ilocalrepositoryfilestorage):
     """File storage when using revlogs and narrow files."""
 
     def file(self, path):