bpo-30306: Add missing NEWS entry (GH-5374)

ncoghlan · web-flow · commit a278ad2faa76 · 2018-01-28T15:14:30.000+10:00
diff --git a/Misc/NEWS.d/next/Library/2018-01-28-14-10-51.bpo-30306.TmKMXi.rst b/Misc/NEWS.d/next/Library/2018-01-28-14-10-51.bpo-30306.TmKMXi.rst
@@ -0,0 +1,4 @@
+contextlib.contextmanager now releases the arguments passed to the
+underlying generator as soon as the context manager is entered. Previously
+it would keep them alive for as long as the context manager was alive, even
+when not being used as a function decorator. Patch by Martin Teichmann.
