Add API notes

dstansby · dstansby · commit c10b2e0a80e3 · 2018-05-06T21:24:26.000+01:00
diff --git a/doc/api/next_api_changes/2018-05-06-DS.rst b/doc/api/next_api_changes/2018-05-06-DS.rst
@@ -0,0 +1,7 @@
+Default value for ``block`` keyword arg standardised to ``True``
+----------------------------------------------------------------
+
+The ``block`` keyword argument that can be supplied to `.pyplot.show()` now
+takes a default value of ``True`` instead of ``None``. The behaviour is
+otherwise the same, and the `.backend_bases.FigureManagerBase.show()` has
+also had this change applied.
