Port Skylands terrain filter (#47)

src/main/resources/data/rivencraft/rivencraft/symbols/feature/skylands.json

@@ -0,0 +1,8 @@
+{
+  "schema_version": 2,
+  "name": "symbol.rivencraft.feature.skylands",
+  "description": "symbol.rivencraft.feature.skylands.description",
+  "category": "rivencraft:feature",
+  "semantics": { "role": "feature", "value": "rivencraft:skylands" },
+  "poem": "Terrain Sky Void Suspension"
+}