[Bug libstdc++/106175] std::prev and next should check for equality with std::begin

[deco33000 at yandex dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106175

--- Comment #8 from KL <deco33000 at yandex dot com> ---
Sending a message to the commitee is like sending a message to void.

Issue resolved.