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

[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)

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Commit messages:
 - 8294090 : Corrects RGBandRGBAalignmentBehaviours.java file permission.
 - 8294090 :
 - Merge master
 - Amélioration de la prise en charge des fonctions rgb et rgba concernant les couleurs.

Changes: https://git.openjdk.org/jdk/pull/15262/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15262&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294090
  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