Validate trailing comma in multi-line function declaration

pull request: https://github.com/pfrenssen/coder/pull/225

Found a better solution by forking our own function declaration multi-line sniff in https://github.com/pfrenssen/coder/pull/226

Merged the latter one.

Automatically closed - issue fixed for 2 weeks with no activity.

Why a custom sniff over SlevomatCodingStandard.Functions.RequireTrailingCommaInDeclaration ?

Hm, I probably did not find that sniff. Good to know that it exists, but with the fork of the upstream PHPCS sniff we cover all our requirements for Drupal, so I think it is fine.

Just a note that if one uses the slevomat version also, multiple errors are reported on a line. One for each rule.