CHANGELOG entry.

CHANGELOG.md

 This file lists "large-ish" changes to the std++ Coq library, but not every
 API-breaking change is listed.
 
+## std++ master
+
+- Disambiguate Haskell-style notations for partially applied operators. For
+  example, change `(!! i)` into `(.!! x)` so that `!!` can also be used as a
+  prefix, as done in VST. A sed script to perform the renaming can be found at:
+  https://gitlab.mpi-sws.org/iris/stdpp/merge_requests/93
+
 ## std++ 1.2.1 (released 2019-08-29)
 
 This release of std++ received contributions by Dan Frumin, Michael Sammler,