#16522: Add FAIL_FAST flag to doctest.
Patch by me, most of the work (doc and tests) by Daniel Urban.
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
index 4bed2ed..ab0b163 100644
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -150,7 +150,11 @@
Improved Modules
================
-* None yet.
+doctest
+-------
+
+Added ``FAIL_FAST`` flag to halt test running as soon as the first failure is
+detected. (Contributed by R. David Murray and Daniel Urban in :issue:`16522`.)
Optimizations