fix typo

Author: tyrasd

data/fields/traffic_calming.json

@@ -14,7 +14,7 @@
             "chicane": "Traffic Chicane",
             "choker": "Traffic Choker",
             "choked_table": "Choked Speed Table",
-            "cushion": "Speed Chushion",
+            "cushion": "Speed Cushion",
             "dip": "Dip",
             "double_dip": "Double Dip",
             "hump": "Speed Hump",