Issue #2270551 : Allow $this as data type in @return docs.

Conflicts:
	coder_sniffer/Drupal/Sniffs/Commenting/FunctionCommentSniff.php
Issue #2203627 by TravisCarden: Fixed "Implements hook_foo() for some-template.file" sniff doesn't support Twig template names.
Issue #2135129 by TravisCarden: Bad Sniff: Perl-style comments.
Issue #2236393 by TravisCarden: Bad test: Inline doc block comments are not allowed.
Issue #2236407 by TravisCarden: Don't impose line length limit on ANY Doxygen directives.