[m-rev.] for post-commit review: add entry to 22.01.9 NEWS

[Julien Fischer]

Add entry to 22.01.9 NEWS.

NEWS:
   Add entry for the recent fix to calendar.duration/2.

Julien.

diff --git a/NEWS b/NEWS
index 224d20a6f..22045bb61 100644
--- a/NEWS
+++ b/NEWS
@@ -26,6 +26,10 @@ This is a bug-fix release.
   strings containing a fractional second component with no whole number part
   (e.g. "PT.5S") were incorrectly being accepted.

+* We have fixed a bug in `calendar.duration/2` that caused it to compute
+  an incorrect duration, or abort, for some pairs of dates whose difference
+  required borrowing days across months of differing length.
+
 * We have fixed bugs in the C# and Java implementations of
   `math.unchecked_log2/1` that caused target language compilation errors
   when compiling with `--intermodule-optimisation`.