Documentation for std.pref not provided online, nor in distro

[Lionello Lunesu]

std.perf!!
in dmd/src/phobos/std/perf.d

Lionello Lunesu wrote:
> dmd/src/phobos/std/pref.d seems to have DDOC comments, but its 
> documentation is nowhere to be found.
> 
> This issue has been reported as early as February 2005:
> http://www.digitalmars.com/d/archives/digitalmars/D/17723.html
> and also:
> http://www.digitalmars.com/d/archives/digitalmars/D/bugs/6894.html
> 
> L.