Adds bem entity description to a doclet.
This method is called after doclet has
been constructed but before it sent to template.
Its required, because automatically inserted
`@block`, `@elem` and `@mod` keys does not
contain names.
@param {Object} e symbolFound event, generated from
`astNodeVisitor`. At this stage should already have
doclet property, which contains parsed docs.
function addDocletBemEntity(e) {
    var bemEntity = e.code.bemEntity;
    e.doclet.block = bemEntity.block;
    if (bemEntity.base) {
        e.doclet.baseBlock = bemEntity.base;
    }
    if (bemEntity.mod) {
        e.doclet.mod = {
            name: bemEntity.mod,
            value: bemEntity.val
        };
    }
}