Remove "std." from library reference menu?

[Andrei Alexandrescu via Digitalmars-d]

Thanks @JinShil! 
https://github.com/D-Programming-Language/dlang.org/pull/827

The con is that some people may find it confusing, thinking they should 
import algorithm instead of std.algorithm etc.

On the other hand the documentation of each module has "std." in clear 
in the heading.


Thoughts?

Andrei