Update links in 2.0/2.1 HELP to new & latest techniques published by W3C in WCAG 2.2

[philljenkins]

• update URLs in all the existing HELP files (~170) to all the latest & new techniques and WCAG references to the newly published WCAG 2.2 resources such as www.w3.org/WAI/WCAG22/Techniques/ published by W3C.
• update links in sc-urls.json, include WCAG 2.2 AAA as well as A & AA
• update links in rues & ruleunits (test cases)
• update links to Unit Tests that moved in Toolkit

example code for each rule help file:
### About this requirement
* [WCAG technique H24](https://www.w3.org/WAI/WCAG21/Techniques/html/H24)

would change to :
### About this requirement
* [WCAG technique H24 Providing text alternatives for the area elements of image maps](https://www.w3.org/WAI/WCAG22/Techniques/html/H24)

All ~170 existing rule Help files that reference techniques and other resources are in
... /accessibility-checker-engine/help-v4/en-US/ ...

[philljenkins]

@shunguoy ready for your review - see PR #1747

[philljenkins]

One of the link changes had a missing ">", which caused a test case to fail in the build. Fixed and now passing. Ready for QA

[philljenkins]

When checking the "Checker rule sets" page via action artifact Rule listing, I found missing definitions for 3 new WCAG 2.2 SCs that don't have any rules yet.

• missing definitions:
  

• Definitions added for new WCAG 2.2 SCs that don't have rules mapped to them
  

[philljenkins]

@ErickRenteria asked for @philljenkins to do a quick showcase playback to review the text changes that add the title to the link text. Such as for each rule help file:

About this requirement

• WCAG technique H24

would change to :

About this requirement

• WCAG technique H24 Providing text alternatives for the area elements of image maps

• Affects all ~170 existing rule Help files that reference techniques that previously had very short cryptic numbers as link text (titles)