RFR: 8308108: Support Unicode extension for collation settings [v2]

[Roger Riggs]

On Thu, 18 May 2023 16:42:23 GMT, Naoto Sato <naoto at openjdk.org> wrote:

>> This change intends to interpret the BCP47 U extension wrt collation settings in the given `Locale`, then applies them to the created instances in the 1-arg factory method in `Collator`. A corresponding CSR has also been drafted.
>
> Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update test/jdk/sun/text/resources/Collator/CollationSettingsTests.java
>   
>   Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>

src/java.base/share/classes/java/text/Collator.java line 236:

> 234:      * setting value is not recognized, strength and/or decomposition will not be
> 235:      * overridden.
> 236:      * @apiNote Implementations of {@code Collator} class may produce

The API should identify the valid values for ks and kk and the corresponding values as passed to setStrength and setDecomposition.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14040#discussion_r1198141303