In commit ef275d1f20 I implemented the
wrong resolution of LWG 3474. This removes the deduction guide and
alters the views::join factory to create the right type explicitly.
libstdc++-v3/ChangeLog:
* include/std/ranges (join_view): Remove deduction guide.
(views::join): Add explicit template argument list to prevent
deducing the wrong type.
* testsuite/std/ranges/adaptors/join.cc: Move test for LWG 3474
here, from ...
* testsuite/std/ranges/adaptors/join_lwg3474.cc: Removed.