Expand help command with morehelp feature

Now you can specify what command you want help on.

Respond if no specific command or help

Add moreHelp for the userinfo command

Use regex to replace <prefix> with actual prefix

commands/userinfo.js

@@ -5,6 +5,7 @@ const creationJoinDates = require("../util/creationJoinDates")
 module.exports = {
 	name: 'userinfo',
 	description: 'Displays information about the user',
+	moreHelp: ["Example: <prefix>userinfo <some_username>","It works with username, nickname, userid, and mention"],
 	execute({message, args}) {
 		let info;
 		let nickname = "";