RFR: JDK-8294090 : Aligns the CSS <rgb()> and <rgba()> function behaviours [v2]

[ScientificWare]

> This is referenced in Java Bug Database as
> - [JDK-8294090 : Aligns the CSS `<rgb()>` and `<rgba()>` function behaviours](https://bugs.java.com/bugdatabase/view_bug?bug_id=8294090)
> 
> This is tracked in JBS as 
> - [JDK-8294090 : Aligns the CSS `<rgb()>` and `<rgba()>` function behaviours](https://bugs.openjdk.java.net/browse/JDK-8294090)
> 
> Aligns the `<rgb()>` and `<rgba()>`  function behaviours in CSS.java, as described in :
> CSS Color Module Level 4
> W3C Candidate Recommendation Snapshot, 5 July 2022
> [4.1 The `<Color>` syntax](https://www.w3.org/TR/css-color-4/#color-syntax)
> [6.1. The RGB functions: rgb() and rgba()](https://www.w3.org/TR/css-color-4/#funcdef-rgb)
> 
> Designed from : [ScientificWare JDK-8294090 : Aligns the CSS <rgb()> and <rgba()> function behaviours](https://github.com/scientificware/jdk/issues/16)

ScientificWare has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:

 - Merge branch 'openjdk:master' into scientificware-patch-004-CSS-aligns_rgb_and_rgba_function_behaviours
 - 8294090 : Corrects RGBandRGBAalignmentBehaviours.java file permission.
 - 8294090 :
   
   CSS.java :
     - Adds links to CSS-COLOR-4 and CSS-VALUE-4 specifications.
     - Update PARSE RGB method comments.
     - Adds base-ten exponent support.
   
   RGBandRGBAalignmentBehaviours.java :
     - Adds a set of tests for RGB functions.
 - Merge master
   
   # Conflicts:
   #	src/java.desktop/share/classes/javax/swing/text/html/CSS.java
 - Amélioration de la prise en charge des fonctions rgb et rgba concernant les couleurs.

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Changes: https://git.openjdk.org/jdk/pull/15262/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15262&range=01
  Stats: 357 lines in 2 files changed: 309 ins; 0 del; 48 mod
  Patch: https://git.openjdk.org/jdk/pull/15262.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15262/head:pull/15262

PR: https://git.openjdk.org/jdk/pull/15262