Port authored Obelisks age feature (#56)

src/main/resources/assets/rivencraft/lang/en_us.json

@@ -285,6 +285,8 @@
   "symbol.rivencraft.feature.trail_ruins.description": "Allow buried trail ruins in compatible surface biomes.",
   "symbol.rivencraft.feature.dense_ores": "Dense Ores",
   "symbol.rivencraft.feature.dense_ores.description": "Repeat compatible vanilla and modded ore placements once per page in this Age.",
+  "symbol.rivencraft.feature.obelisks": "Obelisks",
+  "symbol.rivencraft.feature.obelisks.description": "Add rare tall obelisks on exposed solid ground, with a random or selected block material.",
   "symbol.rivencraft.feature.lava_lakes": "Small Lakes",
   "symbol.rivencraft.feature.lava_lakes.description": "Add small surface lakes using a random fluid, or specify one with a fluid page.",
   "generator.rivencraft.standard": "Standard",

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

@@ -0,0 +1,8 @@
+{
+  "schema_version": 2,
+  "name": "symbol.rivencraft.feature.obelisks",
+  "description": "symbol.rivencraft.feature.obelisks.description",
+  "category": "rivencraft:feature",
+  "semantics": { "role": "feature", "value": "rivencraft:obelisks" },
+  "poem": "Civilization Structure Power Obelisk"
+}