Minecraft: Document tooltip suggestions

We should document how tooltip suggestions work when using Brigadier, and probably mention the preconditions necessary for them to function properly in the platform documentation.

We should also explain how to register https://github.com/Incendo/cloud-minecraft/blob/master/cloud-minecraft-extras/src/main/java/org/incendo/cloud/minecraft/extras/suggestion/ComponentTooltipSuggestion.java.