[Bug libstdc++/102280] span's range deduction guide is missing ranges::contiguous_range constraint

[joeloser93 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102280

--- Comment #4 from Joe Loser <joeloser93 at gmail dot com> ---
Johnathan, your fix LGTM. Safe to mark this as resolved, or do you need to do
something to backport it for the 10.4 release branch?