Lecterns don't add to the maximum level of the Index of Knowledge

[OhBrod]

https://github.com/MinerArcana/Astral/blob/develop/1.16.x/src/main/java/com/alan19/astral/blocks/IndexOfKnowledge.java#L91 I think a multiplication might have been put by error near the end of that line which messes with the calculation.