RFR: 8338882: Clarify matching order of MessageFormat subformat factory styles [v2]

[Justin Lu]

> Please review this PR which clarifies that the matching order of format styles for MessageFormat sub formats is not guaranteed by the JDK implementation. A corresponding CSR has also been drafted.
> 
> This is relevant when a locale provides equivalent patterns for multiple format factory styles. For example, a locale X could provide some equivalent date style "xyz" for both a MEDIUM and LONG style. Thus invoking toPattern() could output `date`, `date,medium`, or `date,long` depending on the order of such matching.

Justin Lu has updated the pull request incrementally with one additional commit since the last revision:

  revise wording

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20695/files
  - new: https://git.openjdk.org/jdk/pull/20695/files/7953073b..8d434f29

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20695&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20695&range=00-01

  Stats: 8 lines in 1 file changed: 3 ins; 4 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/20695.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20695/head:pull/20695

PR: https://git.openjdk.org/jdk/pull/20695