valgrind 3.21.0 supports D demangling

[user456 via Digitalmars-d-announce]

In case some would still pipe valgrind in ddemangle, be aware 
that this is not required anymore. Since [version 3.21.0], 
valgrind supports D demangling out of the box.

[version 3.21.0]: https://valgrind.org/docs/manual/dist.news.html