RFR: 8316135: Create release notes for JavaFX 21 [v3]

Wed Sep 13 12:06:44 UTC 2023

> Release notes for JavaFX 21, including four important changes, and the list of enhancements and bugs fixed in this release.
> 
> I plan to integrate this on Monday, Sep 18th, and backport it to `jfx21` in time for Tuesday's release of JavaFX 21.

Kevin Rushforth has updated the pull request incrementally with one additional commit since the last revision:

  Review feedback: remove libxml2 2.10.3

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1239/files
  - new: https://git.openjdk.org/jfx/pull/1239/files/56120aec..27a3d810

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1239&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1239&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1239.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1239/head:pull/1239

PR: https://git.openjdk.org/jfx/pull/1239