bpo-35907: Clarify the NEWS entry (GH-13523)

Author: vstinner

Misc/NEWS.d/next/Security/2019-05-21-23-20-18.bpo-35907.NC_zNK.rst

@@ -1,2 +1,3 @@
-CVE-2019-9948: Avoid file reading as disallowing the unnecessary URL scheme in
-``URLopener().open()`` ``URLopener().retrieve()`` of :mod:`urllib.request`.
+CVE-2019-9948: Avoid file reading by disallowing ``local-file://`` and
+``local_file://`` URL schemes in ``URLopener().open()``
+``URLopener().retrieve()`` of :mod:`urllib.request`.