[Bug libstdc++/115209] The implementation of concat_view refers to p2542r7 rather than the p2542r8

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115209

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
As already noted at
https://gcc.gnu.org/pipermail/gcc-patches/2024-May/652571.html