RFR: 8316135: Create release notes for JavaFX 21 [v4]

[Kevin Rushforth]

On Sat, 16 Sep 2023 14:01:22 GMT, Nir Lisker <nlisker at openjdk.org> wrote:

>> Kevin Rushforth has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix typo: TreeColumnBase --> TableColumnBase
>
> doc-files/release-notes-21.md line 72:
> 
>> 70: [JDK-8307363](https://bugs.openjdk.org/browse/JDK-8307363)|TextFlow.underlineShape()|graphics
>> 71: [JDK-8299756](https://bugs.openjdk.org/browse/JDK-8299756)|Minor updates in CSS Reference|other
>> 72: [JDK-8306648](https://bugs.openjdk.org/browse/JDK-8306648)|Update the JavaDocs to show the NEW section and DEPRECATED versions|other
> 
> Should we mention somewhere that this doesn't always work properly because of [JDK-8309765](https://bugs.openjdk.org/browse/JDK-8309765)?

This bug doesn't rise to the level of "Important Changes", which are mainly intended to alert developers to possible compatibility issues, so there isn't a good place to add it. I suppose we could add a "Known Bugs" section to list bugs that are either regressions from a prior release or are bugs in newly added features, but I don't want to do that this late in the cycle, especially not without discussing the general idea of whether or not to list known bugs.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1239#discussion_r1327971463