Add first-party MangaPill source and distinct volume releases

scraper/plugins/registry.js

@@ -6,6 +6,7 @@ const { validate } = require('./validation');
 const plugins = Object.freeze({
   weebcentral: require('./weebcentral'),
   mangadex: require('./mangadex'),
+  mangapill: require('./mangapill'),
 });
 
 function parse(plugin, operation, input) {