Allocating a Vector for each of these invocations is a bit silly when
the values are basically all compile-time arrays. This AO is used even
more heavily by Intl.DateTimeFormat, so change it to accept a Span to
reduce its cost.
This also adds an overload to accept a fixed-size C-array so callers do
not have to be prefixed with AK::Array, i.e. this:
get_option(..., AK::Array { "a"sv, "b"sv }, ...);
Reduces to:
get_option(..., { "a"sv, "b"sv }, ...);
(Which is how all call sites were already written to construct a Vector
in place).