[aur-general] Deletion request: graphviz-hg

The source URL in the package [graphviz-hg][1] is dead, and graphviz is now using Git as VCS, a new package is created at [graphviz-git][2]. [1]: https://aur.archlinux.org/packages/graphviz-hg/ [2]: https://aur.archlinux.org/packages/graphviz-git/