[Bug] MethodAnnotationStructureSniff causes error when there is no doc comments in the file

[lenaorobei]

Steps to reproduce

Run phpcs against following code:

<?php

class ClassWithNoAnnotation
{
    protected function methodWithNoAnnotation(){
        //code here
    }
}

Expected result

Warning about missing annotation is displayed.

Actual result

ERROR | An error occurred during processing; checking has been aborted. The error message was: Undefined index: comment_closer in magento-coding-standard/Magento/Sniffs/Annotation/MethodAnnotationStructureSniff.php on line 48 (Internal.Exception)

[lenaorobei]

Closing since rules under Annotation section were removed due to unsuitability.
See #54 and #58.