Maximum length of book title changed from 16 to 15 characters

The bug

When signing a book and quill it only allows you to enter 15 characters. It has always been 16 in the past.

How to reproduce

1. Take a book and quill item

   /give @s minecraft:writable_book
   

2. Try to sign it with a title of exactly 16 characters
3. Notice that it only allows 15 characters

Code analysis

The issue is that the field titleEdit in net.minecraft.client.gui.screens.inventory.BookEditScreen checks if the length is < 16. Replacing this with <= 16 fixes the issue.