This commit has no behavior changes.
In particular, this does not fix any of the wrong uses of the previous
default parameter (which used to be 'false', meaning "only replace the
first occurence in the string"). It simply replaces the default uses by
String::replace(..., ReplaceMode::FirstOnly), leaving them incorrect.
This also required converting URLSearchParams::for_each and the callback
function it invokes to ThrowCompletionOr. With this, the ReturnType enum
used by WrapperGenerator is removed as all callers would be using
ReturnType::Completion.
The new URL built-in that will reside in URL.{h, cpp} will have an
URLSearchParams member, which means it has to include its header, and
as such URLSearchParams.h can't include URL's header, which it needs as
it uses the url_{encode, decode} functions.
This is a very partial implementation, as some features (like 2 of the
possible constructor types, iteration and the getAll method) are
missing, and other's are not implemented due to the currently missing
URL built-in.
This namespace will be used for all interfaces defined in the URL
specification, like URL and URLSearchParams.
This has the unfortunate side-effect of requiring us to use the fully
qualified AK::URL name whenever we want to refer to the AK class, so
this commit also fixes all such references.
