Hi! 
First of all, thanks for the contribution!
It would have helped to share a quick link to the PR, though it was trivial to find.
I鈥檒l begin (here) by explaining how it got only reviewed, but not merged.
Anyone with a GitHub account can leave a review for any PRs on GitHub. Those reviews are those with a gray-background checkmark. Those users generally have no special rights. Some may be in the maintainers group of the NixOS organization, but this organization has no special rights in the organization (details in rfcs#39). With that said, those reviews are encouraged, and helpful. First, this is a way to build-up trust in that user. Then, especially with trust, this helps committers know this is a more likely candidate for merge.
Why isn鈥檛 it merged? Most likely because of random misfortune. Nixpkgs receives a lot of contributions.
What to do when no committers come across your PR? Well, you鈥檝e mostly done it! Get in touch. Some PRs are less of a priority, so around a week is before poking is likely the sweet spot. Though, some software is more important to get merged in due time, one of those class is web browsers, especially when there is a security issue.
With that said, I think posting to the PRs already reviewed topic would be preferred, rather than making a new topic each time. Another location where you may get some eyes and hands on your PRs is the IRC channel, #nixos on freenode.net (no guarantees there).
Now goes handling #80592