[Bug libstdc++/93983] std::filesystem::path is not concept-friendly

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93983

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Paco Arjonilla from comment #4)
> There is no reason why an extra constructor would affect the semiregularity
> of a type.

That's not true.

A private or deleted constructor that is a better match for some arguments can
affect it.