I don't see this an "announcement of an announcement", as there's concrete and detailed content about the announcement itself. You can read the commit message and even the source code.

Moreover, I'm not affiliated with Citus and I don't know if they are planning later on an official announcement or not.

I stand by the idea of sharing these good news at the earliest for everyone interested to know, look at the code, and plan ahead of time if they need/want to.