Add context logging in Selectors.register

Author: agg23

playwright/_impl/_selectors.py

@@ -44,6 +44,9 @@ async def register(
         engine: Dict[str, Any] = dict(name=name, source=script)
         if contentScript:
             engine["contentScript"] = contentScript
+        print(
+            f"Registering selector engine: {name} with contexts {self._contextsForSelectors}"
+        )
         for context in self._contextsForSelectors:
             await context._channel.send(
                 "registerSelectorEngine", dict(selectorEngine=engine)