Add more information when an InvalidTag occurs and a link to the phpDocumentor documentation #346

In issue phpDocumentor/phpDocumentor#3378, there was some confusion because the Author tag does not support a description. When the StandardTagFactory encounters a situation where an InvalidTag is generated, it would be nice if it could ask the Tag class what the expected format is and a link to the documentation; and include that in the InvalidTag so that phpDocumentor can provide better error messages in the error report