Cleanup: include otherwise unused imports in __all__

Suppresses unused import warnings with "ruff check".

scripts/modules/bpy/__init__.py

@@ -10,6 +10,7 @@ __all__ = (
     "app",
     "context",
     "data",
+    "msgbus",
     "ops",
     "path",
     "props",

scripts/modules/bpy/utils/toolsystem.py

@@ -2,6 +2,10 @@
 #
 # SPDX-License-Identifier: GPL-2.0-or-later
 
+__all__ = (
+    "ToolDef",
+)
+
 # Until we untangle ToolDef from bl_ui internals,
 # use this module to document ToolDef.
 from bl_ui.space_toolsystem_common import ToolDef