Is Microsoft SQL Server 2016 fully ANSI SQL-92 compliant?

I don't believe that any version of any database platform on earth is fully compliant with any version of the standard. This is probably why you're not finding any claims of 100% compliance...

You can find some promising starting points over on Stack Overflow in the following Q & A: Database Engines and ANSI SQL Compliance

Many references linked from there are not maintained because database platforms are evolving all the time and this would be many full-time jobs to stay on top of it all. Basically:

• no database platform is 100% compliant, but several come close
• platforms have proprietary additions on top of the standard, so your definition of "fully compliant" may vary from someone else's