docs: minor updates

docs/tasks.rst

@@ -153,6 +153,7 @@ The task will then be injected straight into a worker and the result saved by a
     An error occurred: ImportError("No module named 'my'",)
 
 Note that :func:`async` will block until the task is executed and saved. This feature bypasses the Redis server and is intended for debugging and development.
+Instead of setting ``sync`` on each individual ``async`` you can also configure :ref:`sync` as a global override.
 
 Connection pooling
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