RFR: 8357393: RichTextArea: fails to properly save text attributes [v2]

[Andy Goryachev]

> Fixing a bug that breaks proper serialization of character attributes.
> 
> This, unfortunately, makes a breaking change in the RichTextArea native format [0].
> 
> ## References
> 
> [0] https://github.com/andy-goryachev-oracle/Test/blob/main/doc/RichTextArea/RichTextArea_DataFormat_V2.md

Andy Goryachev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into 8357393.attr.ser
 - javadoc
 - Merge remote-tracking branch 'origin/master' into 8357393.attr.ser
 - test
 - tests
 - fixed attribute serialization

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1813/files
  - new: https://git.openjdk.org/jfx/pull/1813/files/06b31815..147502bf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1813&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1813&range=00-01

  Stats: 572 lines in 26 files changed: 522 ins; 12 del; 38 mod
  Patch: https://git.openjdk.org/jfx/pull/1813.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1813/head:pull/1813

PR: https://git.openjdk.org/jfx/pull/1813