Make diamond and emerald blocks chisel-able

[eturner]

This looks like some sort of work around because it doesn't get rid of the empty chisel block groups for diamond and emerald blocks, but it works. I just copied the previously applied fix for lapis blocks, which also has an empty chisel block group.

[CLAassistant]

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[eturner]

There's a problem with the blocks in multiple chisel groups in that the iChisel GUI can neither make the vanilla block chiseled, nor make a chiseled block vanilla again. It needs to be put on the ground and left-clicked or used with the regular chisel GUI.
So far I've only noticed in game that lapis and coal blocks have multiple groups. There's probably others. Couldn't hurt to add diamond and emerald until somebody figures this out.