[Bug libstdc++/82685] basic_string_view operator""sv(const char*, size_t) should be noexcept

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82685

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
N.B. the compiler already gives the right answer when asked:

#include <string_view>
using namespace std::literals::string_view_literals;
static_assert(noexcept(""sv"));

So the fact we don't say 'noexcept' doesn't actually matter.