Issue 6737 - Use String.includes instead of String.indexOf

lib/common.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 46 matching lines @@
     // remove leading wildcards
     .replace(/^(\.\*)/, "")
     // remove trailing wildcards
     .replace(/(\.\*)$/, "");
 }
 
 exports.filterToRegExp = filterToRegExp;
 
 function splitSelector(selector)
 {
-  if (selector.indexOf(",") == -1)
+  if (!selector.includes(","))
     return [selector];
 
   let selectors = [];
   let start = 0;
   let level = 0;
   let sep = "";
 
   for (let i = 0; i < selector.length; i++)
   {
     let chr = selector[i];
@@ skipping 16 matching lines @@
         start = i + 1;
       }
     }
   }
 
   selectors.push(selector.substring(start));
   return selectors;
 }
 
 exports.splitSelector = splitSelector;