JEP proposed to target JDK 17: 406: Pattern Matching for switch (Preview)

[Florian Weimer]

* mark reinhold:

> The following JEP is proposed to target JDK 17:
>
>   406: Pattern Matching for switch (Preview)
>        https://openjdk.java.net/jeps/406
>
>   Summary: Enhance the Java programming language with pattern matching
>   for switch expressions and statements, along with extensions to the
>   language of patterns.  Extending pattern matching to switch allows
>   an expression to be tested against a number of patterns, each with a
>   specific action, so that complex data-oriented queries can be expressed
>   concisely and safely.

I think the formatter(Object) and formatterPatternSwitch(Object)
example implementations should be aligned ("unknown" vs o.String()).