Update django_mongodb_backend/routers.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: aclark4life

django_mongodb_backend/routers.py

@@ -20,6 +20,7 @@ def allow_migrate(self, db, app_label, model_name=None, **hints):
         return False if issubclass(model, EmbeddedModel) else None
 
 
+# This function is intended to be monkey-patched as a method of ConnectionRouter.
 def kms_provider(self, model, *args, **kwargs):
     for router in self.routers:
         func = getattr(router, "kms_provider", None)