[jfx20] RFR: 8304359: Create release notes for JavaFX 20 [v2]

[Kevin Rushforth]

> Release notes for JavaFX 20, including one important change to note (the requirement of JDK 17 as the minimum needed to run JavaFX 20) and the list of enhancements and bugs fixed in this release.
> 
> Note: This PR is targeted to `jfx20`.

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

  Add missing FXMLLoader note

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1060/files
  - new: https://git.openjdk.org/jfx/pull/1060/files/81a43a29..f972b19d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1060&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1060&range=00-01

  Stats: 10 lines in 1 file changed: 10 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1060.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1060/head:pull/1060

PR: https://git.openjdk.org/jfx/pull/1060