RFR (CSR) JDK-8245399 Remove addition preview adornment from String::formatted

[Paul Sandoz]

+1
Paul.

> On May 19, 2020, at 1:00 PM, Jim Laskey <james.laskey at oracle.com> wrote:
> 
> Please review this change to remove the preview heading from the javadoc of String::formatted. This also updates the @since to 15.
> 
> Thank you.
> 
> Cheers,
> 
> -- Jim
> 
> 
> csr: https://bugs.openjdk.java.net/browse/JDK-8245399 <https://bugs.openjdk.java.net/browse/JDK-8245399>
> jbs: https://bugs.openjdk.java.net/browse/JDK-8245398 <https://bugs.openjdk.java.net/browse/JDK-8245398>
> 
>