Keeping `wiki.json` up to date

[TheBusyBiscuit]

Description

In your Slimefun Guide some items will get a button that says "click to see the wiki article for this item".
In order for this button to appear, an item needs to be linked to a wiki page.
We currently achieve this linkage by maintaining a wiki.json file:

https://github.com/Slimefun/Slimefun4/blob/master/src/main/resources/wiki.json

📍 This pinned issue should serve as a reminder to any contributors to keep that file up to date from time to time :)