JFormValidator to pass element to handler
Fixing getArticleRoute() calls

There is no need to use catslug in Joomla 3.x because:
1. Core content component doesn't use catslug in article URLs;
2. Process link function - **ContentHelperRoute::getArticleRoute** - requires only catid.
`/components/com_content/helpers/route.php`
`public static function getArticleRoute($id, $catid = 0, $language = 0)`

See more #4371 and #5276

After this PR all URLs to the articles must be identical as in content component.
Fixing getArticleRoute() calls

There is no need to use catslug in Joomla 3.x because:
1. Core content component doesn't use catslug in article URLs;
2. Process link function - **ContentHelperRoute::getArticleRoute** - requires only catid.
`/components/com_content/helpers/route.php`
`public static function getArticleRoute($id, $catid = 0, $language = 0)`

See more #4371 and #5276

After this PR all URLs to the articles must be identical as in content component.
Namespace install app field/rule classes
Update README.md

updated few Migration links to the JDocs
Update README.txt

Few migration links updated
Update README.txt

docs links -> https
Merge pull request #5480 from MAT978/patch-11

Update README.txt
Update README.md

docs links -> https
API site serves all traffic via HTTPS
Merge pull request #5479 from MAT978/patch-10

Update README.md
Merge pull request #5481 from mbabker/APIlinks

API site serves all traffic via HTTPS
 en-GB only: correcting Hyphenation (Fixes #5483 )
 Fixes listing of "All" categories (#4937) (Fixes #5469 )
 Update installation/model/languages.php (Fixes #5331 )
Merge pull request #5426 from shur/patch-10

[fix] Fixing getArticleRoute() calls in featured default_links
Merge pull request #5427 from shur/patch-11

[fix] Fixing getArticleRoute() calls in finder content plugin
Fix the jumping toolbar
Undefined property: stdClass::$language in
/modules/mod_articles_news/helper.php on line 93
Prefer HTTPS for the help screen proxy