Fabric: support for multiple simulatenous graves

[alexweber]

Hi there, not sure if there's a config for this I'm missing but if you die trying to retrieve your grave, a new grave is generated as expected but breaks the old grave.

Steps to replicate:

• In creative mode give yourself some gear and inventory items
• Spawn a few creepers and switch to Survival and let them kill you
• Switch back to creative upon respawn, give yourself some more items and repeat the entire process - preferrably close to the first grave that spawned
• Now there's 2 graves as expected but only the second one works, the first one doesn't do anything anymore

Thanks!