Sulfur spring structure templates do not use the "minecraft" namespace

All vanilla content should have a namespace of minecraft however the sulfur spring structures instead use sulfur_spring as their namespace.

Steps to reproduce:

• Create a world with cheats and the “Drop 2 of 2026“ experiment enabled

• Run the following command: /structure load sulfur_spring:sulfur_spring_small_1 ~~~

Observed results:

• The structure is successfully loaded with the namespace sulfur_spring.

• This is caused by the .mcstructure files being located at structures/sulfur_spring

Expected results:

• The .mcstructure files should be located at structures/minecraft/sulfur_spring

• This would give the structure templates the correct namespace e.g. minecraft:sulfur_spring/sulfur_spring_small_1

• The command would then only succeed when the minecraft namespace is used /structure load "minecraft:sulfur_spring/sulfur_spring_small_1" ~~~