Different Double Slabs

This release is compatible with all versions 1.20.0 and up!*

*The only caveat is that the resource pack won't automatically have support for any new slabs added after 1.21.0, so message me on Discord reminding me to add them! (@owehttamy)

Changes:

• Fixed a mistake in mod support directions and template regarding namespaces (Thanks @peow. on Discord!)