fixed documentation in sdks/python/apache_beam/io/gcp/pubsub.py Write…

…ToPubSub (apache#30285)

* fixed documentation in sdks/python/apache_beam/io/gcp/pubsub.py writetopubsub

* Update build.gradle - I accidentally removed a character in a previous commit

* Update pubsub.py

* fixed linting error

sdks/python/apache_beam/io/gcp/pubsub.py

@@ -337,7 +337,9 @@ def __init__(
     """Initializes ``WriteToPubSub``.
 
     Args:
-      topic: Cloud Pub/Sub topic in the form "/topics/<project>/<topic>".
+      topic:
+          Cloud Pub/Sub topic in the form
+          "projects/<project>/topics/<topic>".
       with_attributes:
         True - input elements will be :class:`~PubsubMessage` objects.
         False - input elements will be of type ``bytes`` (message