[PATCH] Update links to libstdc++ Doxygen pages

[Gerald Pfeifer]

On Mon, 22 Aug 2016, Jonathan Wakely wrote:
> There's no reason to have a fixed list of release versions in the
> libstdc++ docs which needs updating manually. The page at
> https://gcc.gnu.org/onlinedocs already links to the Doxygen docs for
> each release, so we can just refer to that.
> 
> 	* doc/xml/api.xml: Replace hardcoded links for specific versions with
> 	link to docs for all releases.
> 	* doc/html/*: Regenerate.

Makes a lot of sense!

> Committed to trunk. I'll probably backport this to gcc-5 and gcc-6,
> because the list of releases on those branches haven't been updated to
> refer to anything later than 4.9.2

This, too. :-)

Gerald