Fix copy-paste typo

Author: sergey-miryanov

Doc/library/asyncio-dev.rst

@@ -300,7 +300,7 @@ Avoid iterating and closing the same generator concurrently
 -----------------------------------------------------------
 
 Async generators may to be reentered while another
-:meth:`~agen.aclose`/:meth:`~agen.aclose`/:meth:`~agen.aclose` call is in
+:meth:`~agen.anext`/:meth:`~agen.athrow`/:meth:`~agen.aclose` call is in
 progress. This may lead to an inconsistent state of the async generator
 and can cause errors.