Require implementations for warnings.showwarning() support the 'line' argument.
Was a DeprecationWarning for not supporting it since Python 2.6.

Closes issue #3652.
diff --git a/Misc/NEWS b/Misc/NEWS
index 760badf..5af7df7 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and Builtins
 -----------------
 
+- Issue #3652: Make the 'line' argument for warnings.showwarning() a
+  requirement.  Means the DeprecationWarning from Python 2.6 can go away.
+
 - Issue #5247: Improve error message when unknown format codes are
   used when using str.format() with str, unicode, long, int, and
   float arguments.