RFR: 8378366: Accessibility issues in CSS Reference Guide and Introduction to FXML [v5]

[Andy Goryachev]

> Addressing the accessibility issues in JavaFX CSS Reference Guide and Introduction to FXML documents:
> 
> [JDK-8378306](https://bugs.openjdk.org/browse/JDK-8378306) In JavaFX CSS Reference Guide, a `<ul>` element must appear within an `<li>` element
> [JDK-8378308](https://bugs.openjdk.org/browse/JDK-8378308) In JavaFX CSS Reference Guide, <textarea> elements do not contain a label
> [JDK-8378309](https://bugs.openjdk.org/browse/JDK-8378309) In JavaFX CSS Reference Guide and Introduction to FXML, there are color contrast issues
> [JDK-8378310](https://bugs.openjdk.org/browse/JDK-8378310) In JavaFX CSS Reference Guide and Introduction to FXML, a "Skip to Main Content" link doesn't exist
> [JDK-8378307](https://bugs.openjdk.org/browse/JDK-8378307) In JavaFX CSS Reference Guide, some tables don't use the scope attribute or the <caption> element
> 
> For ease of reviewing, the first 5 commits correspond to individual tickets.
> 
> In [JDK-8378308](https://bugs.openjdk.org/browse/JDK-8378308) the `<textarea>`s were made read-only because obviously.
> 
> Additional issues that came about during the review (both accessibility- and code-):
> 
> - fixed `BoderPane` typo
> - added missing `scope` attribute to `<th>` 
> - moved inline style in the "layout" table to CSS
> - fixed shaded table cell contrast

Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:

  th scope

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/2082/files
  - new: https://git.openjdk.org/jfx/pull/2082/files/25e4f9da..33a43931

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=2082&range=04
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2082&range=03-04

  Stats: 9 lines in 1 file changed: 0 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jfx/pull/2082.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/2082/head:pull/2082

PR: https://git.openjdk.org/jfx/pull/2082