Do some cleanup and typing in RBTools config/options code.

This change does some cleanup, typing, and general modernization in
preparation for allowing config namespacing.

Testing Done:
Ran unit tests.

Reviewed at https://reviews.reviewboard.org/r/14218/

rbtools/clients/__init__.py

@@ -38,7 +38,7 @@
 import logging
 import os
 import sys
-from typing import Optional, TYPE_CHECKING, Tuple
+from typing import Optional, TYPE_CHECKING
 
 from housekeeping import ClassMovedMixin
 
@@ -113,7 +113,7 @@ def scan_usable_client(
     config: RBToolsConfig,
     options: argparse.Namespace,
     client_name: Optional[str] = None,
-) -> Tuple[RepositoryInfo, BaseSCMClient]:
+) -> tuple[RepositoryInfo, BaseSCMClient]:
     """Scan for a usable SCMClient.
 
     Args:
@@ -256,7 +256,6 @@ def scan_usable_client(
     'PatchResult',
     'RepositoryInfo',
     'SCMCLIENTS',
-    'SCMClient',
     'load_scmclients',
     'scan_usable_client',
     'scmclient_registry',

rbtools/clients/base/repository.py

@@ -6,9 +6,10 @@
 
 from __future__ import annotations
 
-from typing import List, Optional, Union
+from typing import List, Optional, TYPE_CHECKING, Union
 
-from rbtools.api.resource import ItemResource
+if TYPE_CHECKING:
+    from rbtools.api.resource import ItemResource
 
 
 class RepositoryInfo:
@@ -159,7 +160,7 @@ def set_base_path(
     def update_from_remote(
         self,
         repository: ItemResource,
-        info: ItemResource,
+        info: Optional[ItemResource],
     ) -> None:
         """Update the info from a remote repository.