Update sqlmesh/core/linter/rules/builtin.py

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

Author: benfdking

sqlmesh/core/linter/rules/builtin.py

@@ -116,8 +116,8 @@ class NoUnregisteredExternalModels(Rule):
     def check_model(self, model: Model) -> t.Optional[RuleViolation]:
         depends_on = model.depends_on
 
-        # Ignore external models themselves, because either they are registered
-        # if they are not, they will be caught as referenced in another model.
+        # Ignore external models themselves, because either they are registered,
+        # and if they are not, they will be caught as referenced in another model.
         if isinstance(model, ExternalModel):
             return None