Widen bpy.msgbus key param to accept any RNA-backed object

subscribe_rna and publish_rna accept any RNA-backed Python object as key
(Vector, Euler, type objects, bl_rna, etc.), not just Property | Struct.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

overrides/5.1/bpy.msgbus.json

@@ -0,0 +1,12 @@
+{
+  "subscribe_rna": {
+    "params": {
+      "key": "bpy.types.Property | bpy.types.Struct | tuple[bpy.types.Struct, str] | object"
+    }
+  },
+  "publish_rna": {
+    "params": {
+      "key": "bpy.types.Property | bpy.types.Struct | tuple[bpy.types.Struct, str] | object"
+    }
+  }
+}