After writing in the book and signing it, the expected behavior is that the now written book should have whatever name you gave the book when signing. However, it keeps its custom name component instead.

Steps to Reproduce:

1. Give yourself a named Book and Quill:

   /give @s writable_book[item_name="test"]
   

2. Click 'Sign'
3. Enter a name
4. Sign and close the book

Expected Result:

The name the player chooses for the written book item when they sign the book and quill would take precedent over the item component name of the book and quill item.

Observed Result:

The written book's name is the same as before it was signed. In this case, "test" instead of whatever you enter as the name.