Fix typos in console messages

Author: xakon

00-introduction.js

@@ -1,3 +1,3 @@
-console.log('Welcome toJavaScript');
-console.log('Congratulations! You wrote you first JavaScript code.');
+console.log('Welcome to JavaScript');
+console.log('Congratulations! You wrote your first JavaScript code.');
 console.log('Welcome to JavaScript for Everyone');