Header search customisation

Thanks for a great theme! I found that we can customise the search: “When you search for content in Sullivan, the results show up immediately next to the search box. A setting in the Customizer allows you to limit the results to specific post types. If you’re running a WooCommerce store, you can set it to only display products in the results, for instance.” However, I do not see this setting in the Customizer.

I’d love to be able to change the message “We could not find anything that matches your search query. Please try again.” as well as “Show n results” so I can translate it. Is there a way to do this? Thank you ??

The page I need help with: [log in to see the link]