Sorted container documentation not updated on github.io

[StephenVavasis]

In PR #787, which was merged yesterday, the documentation for sorted containers is rewritten extensively using Documenter.jl. However, the documentation updates are not yet pushed here: https://juliacollections.github.io/DataStructures.jl/latest/sorted_containers/ and I don't know if additional steps are necessary to get the new docs up.