Changed alternative php-includepath to priority path

[vol4onok]

• PHPMD version: 2.12.0
• PHP Version: 7.4
• Installation type: (composer)
• Operating System / Distribution & Version: (Linux)

Current Behavior

For now you can use php-includepath setting as an alternative path. It means that you try to find a ruleset with pathes from get_include_path() ini setting then you try to find that with <php-includepath> setting.

Expected Behavior

Proposition to use <php-includepath> as priority path instead of alternative. It means that paths from this setting should be added at the beginning of the include_path ini setting.

Steps To Reproduce:

if you use ruleset path that exist with some path from get_include_path(). it make it impossible to use that with a path <php-includepath>. Anyway you return the path from existing pathes from get_include_path().

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• If possible I added relevant code examples.
• This issue is about 1 bug and nothing more.
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Code example.

PHPMD\RuleSetFactory::224 line
Proposition to change
$includePath = get_include_path() . PATH_SEPARATOR . $includePath;
to
$includePath .= PATH_SEPARATOR . get_include_path();.