[phobos] [dlang/phobos] 77a2cb: Move unit test so it makes it into the docs

[GitHub via phobos]

  Branch: refs/heads/fixconvdocs
  Home:   https://github.com/dlang/phobos
  Commit: 77a2cb42d2a7e003e4663b1d9b991aa10c0fa7c3
      https://github.com/dlang/phobos/commit/77a2cb42d2a7e003e4663b1d9b991aa10c0fa7c3
  Author: Steven Schveighoffer <schveiguy at yahoo.com>
  Date:   2016-06-30 (Thu, 30 Jun 2016)

  Changed paths:
    M std/conv.d

  Log Message:
  -----------
  Move unit test so it makes it into the docs