[Bug c++/68257] Reject empty abi_tag attribute on inline namespace

[sbergman at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68257

--- Comment #6 from Stephan Bergmann <sbergman at redhat dot com> ---
Created attachment 36974
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36974&action=edit
updated documentation patch

(In reply to Jonathan Wakely from comment #5)
> is used as <ins>the</ins> ABI tag

yeah, probably sounds better