docs: update docstring for bigquery_create_routine sample (#883)

Fixed language issues.

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Fixes #<issue_number_goes_here> 🦕

samples/create_routine.py

@@ -22,7 +22,7 @@ def create_routine(routine_id):
     # Construct a BigQuery client object.
     client = bigquery.Client()
 
-    # TODO(developer): Choose a fully-qualified ID for the routine.
+    # TODO(developer): Choose a fully qualified ID for the routine.
     # routine_id = "my-project.my_dataset.my_routine"
 
     routine = bigquery.Routine(