Multisite subdirectory installation: can’t save site settings

Hi Noah

Thanks for this awesome plugin. I love how it’s simple and clean!

I noticed a tiny but annoying bug when using the plugin on multisite installations in the subdirectory mode: The form url on the plugins settings page doesn’t respect the subdirectory of the multisite instance. The following screenshot illustrates the problem: https://pasteboard.co/pFvkYTbNriRw.png

The problem should be easy to fix through the use of admin_url().

Have an excellent day,
Cyrill