[Bug libstdc++/101258] std ::is_integral_v is undocumented

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101258

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
While it would be nice if the libstdc++ API docs were 100% complete and
described every piece of the library, that is never going to happen. If you are
trying to use those docs to learn C++ you should stop, and look elsewhere.

The API of libstdc++ is what is described in the standard, and cppreference.com
does a better job of documenting it than we ever will.

So unless we suddenly run out of new features to implement and bugs to fix, I
don't think anybody is going to add documentation for everything like that.

I have regenerated the latest-doxygen docs to include C++17 features:
https://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/index.html
No is_integral_v is listed (with no description) at:
https://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01625.html#a824c5eb1a7e8aafa382dc9af3329a9e8