This is meant to serve as the method all Ladybird chromes can use to
highlight the eTLD+1 substring of the URL. It uses the Public Suffix
List to break the URL into 3 parts: the scheme and subdomain, the
eTLD+1, and all remaining parts (port, path, query, etc.).
We currently implement several forms of this method across the Ladybird
chromes. As such, we see commits to add special URL handling that only
affects a single chrome. Instead, let's consolidate all special handling
in a single location for all chromes to make use of.
This method can handle resolving file:// URLs, falling back to a search
engine query, and validation against the Public Suffix List. These cases
were gathered from the various chromes.
