Fix typo for material=conrete -> concrete (#1245)

Resolves #1244

Author: Dimitar5555

data/fields/material.json

@@ -18,7 +18,7 @@
             "marble": "Marble",
             "metal": "Metal",
             "plastic": "Plastic",
-            "reinforced_conrete": "Reinforced Concrete",
+            "reinforced_concrete": "Reinforced Concrete",
             "rock": "Rock",
             "sand": "Sand",
             "sandstone": "Sandstone",