DocBlock comment enforcement

[ofbeaton]

Make a ruling on how a DocBlock comment should look. Implement a Sniff to enforce it.

Here's a good start:

/**
 * @file
 * @since 2015-07-27
 */

First of all, DocBlock comments can be incredibly redundant. The @since here will match the @since in a class comment.

For this reason, one thing to consider would be to require the absence of a docBlock for class, interface and trait files. Only in mixed or runner script files should it be required, and then a short description should be required as well.

A sensus of popular documentator software should be made to figure out if @file is required or not, and to see how much worth a docBlock has.

Some issues with the current Generic.Commenting.DocComment:

• Generic.Commenting.DocComment.NonParamGroup should have a fix to simply add a blank line
• Generic.Commenting.DocComment.MissingShort should we disallow the absence of short descriptions?