RFR: 8354478: Improve StageStyle documentation [v2]

[Thiago Milczarek Sayao]

> Improve StageStyle Documentation
> 
> - Update `StageStyle.UTILITY`:
> Clarified that UTILITY stages may impose platform-specific restrictions on window states, such as preventing maximize, minimize (iconify), and fullscreen operations.
> 
> - Update `StageStyle.UNDECORATED`:
> Improved the description to clarify that although UNDECORATED removes standard window decorations (title bar, borders, and controls), window operations like minimize, maximize, and fullscreen may still be allowed programmatically or via platform-specific functions such as key shortcuts or menu options.
> 
> - Remove mention of solid white background:
> This seems to be not true anymore, even withou a `Scene` (or there's a bug)

Thiago Milczarek Sayao has updated the pull request incrementally with two additional commits since the last revision:

 - Add "style" ib the UTILITY style like the others
 - Update modules/javafx.graphics/src/main/java/javafx/stage/StageStyle.java
   
   Co-authored-by: John Hendrikx <john.hendrikx+github at gmail.com>

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1776/files
  - new: https://git.openjdk.org/jfx/pull/1776/files/21792071..88307f0d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1776&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1776&range=00-01

  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1776.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1776/head:pull/1776

PR: https://git.openjdk.org/jfx/pull/1776