In gitbooks.io, the link to lesson 6 is broken

[The link](https://monsterdeveloper.gitbook.io/java-telegram-bot-tutorial/lesson-6.-inline-keyboards-and-editing-messages-text) to lesson 6 on `getbook.io` works, but the [link](https://monsterdeveloper.gitbooks.io/writing-telegram-bots-on-java/content/lesson-6.-inline-keyboards-and-editing-message's-text.html) on `getbooks.io` doesn't work.