Merge pull request ethereum#726 from liorsbg/patch-1

Docs - missing parentheses in Filters async example

Author: carver

docs/filters.rst

@@ -229,7 +229,7 @@ entries to a handler.
                     loop.run_until_complete(
                         asyncio.gather(
                             log_loop(block_filter, 2),
-                            log_loop(tx_filter, 2))
+                            log_loop(tx_filter, 2)))
                 finally:
                     loop.close()