Cannot /give or /clear a written_book

How to reproduce

1. Try to give yourself a written book

/give @s written_book 

→ Notice that written_book is not recognized as a valid item id

1. Take a writable_book from the creative menu and sign it
2. Try to clear the written book

/clear @s written_book 

→ Notice that written_book is not recognized as a valid item id