docs: update to use query_and_wait in `client_query_w_positional_pa…

…rams.py` (#1786)

* Updates file

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* Correcting RowIterator

* Variable corrections

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Tim Swast <swast@google.com>

samples/client_query_w_positional_params.py

@@ -35,8 +35,10 @@ def client_query_w_positional_params() -> None:
             bigquery.ScalarQueryParameter(None, "INT64", 250),
         ]
     )
-    query_job = client.query(query, job_config=job_config)  # Make an API request.
+    results = client.query_and_wait(
+        query, job_config=job_config
+    )  # Make an API request.
 
-    for row in query_job:
+    for row in results:
         print("{}: \t{}".format(row.word, row.word_count))
     # [END bigquery_query_params_positional]