Issue Description:

What happens: I go to exit my single player world and everytime minecraft crashes and gives me an error, never happens in mutiplayer, I also confirmed this also works on new worlds. (I'll include a screenshot of my mods)

https://user-images.githubusercontent.com/66574976/83981665-980a2400-a8e5-11ea-9ed6-510d1ab5a650.png

What you expected to happen: Exit to main screen without crashing

Steps to reproduce:

[crash-2020-06-07_17.17.42-client.txt] https://github.com/MisterPeModder/ShulkerBoxTooltip/files/4743143/crash-2020-06-07_17.17.42-client.txt

1. Load up any single player world
2. Exit and Save
3. Crashes
   ...

Affected Versions (Do not use "latest"):

• ShulkerBoxTooltip: 2.02
• Minecraft: 1.15.2
• Fabric Loader: 0.8.7 Build 201
• Fabric API: 0.11.1 Build 312
• Other mods (if relevant): (Included Screenshot)

Your most recent log file where the issue was present:

[pastebin/gist/etc link here]

I have fixed this bug in the 1.16 branch, will backport the fix to 1.15 soon

The issue should be fixed now, the update will be available on curseforge shortly

Thank you, you mod is very useful, have a good day ^^