Add CHANGES entry for #379 on Util.Pp

Author: shym

CHANGES.md

@@ -2,6 +2,10 @@
 
 ## Next
 
+- #379: Extend the set of `Util.Pp` pretty-printers and teach them to
+  add break hints similar to `ppx_deriving.show`; teach `to_show` to
+  generate truncated strings when `$MCTUTILS_TRUNCATE` environment
+  variable is set
 - #368: Switch `STM_domain.agree_prop_par_asym` from using
   `Semaphore.Binary` to using an `int Atomic.t` which improves
   the error rate across platforms and backends