Update blockbestsellers.tpl

- Best sellers module has various titles through all PrestaShop. "Top sellers", "Best sellers", "Top-selling products" etc. I trying to harmonize all titles for one function

- Link title should be different from link anchor text and should be tell user what happend or what you get, when click on the link.
For more information learn e.g. here: http://www.searchenginejournal.com/how-to-use-link-title-attribute-correctly/7687/