Product reference only shown if manufacturer is set

[tswfi]

If product does not have manufacturer set the product reference wont be shown.

See here: https://github.com/PrestaShop/hummingbird/blob/develop/templates/catalog/_partials/product-details.tpl#L17

Also the block naming is kinda misleading as the block is named product_reference but it contains both manufacturer and reference information.

Also would be really nice to have specific class for each detail li element. Maybe the detail__title information could be used to generate class for the li (does smarty have a slugify formatter)? That would allow doing things like highlighting one specific detail with just css.