Update PhysicsCar3DKeyMapper description

Don't show in changelog

Author: 4ian

extensions/reviewed/PhysicsCar3DKeyMapper.json

@@ -10,7 +10,7 @@
   "previewIconUrl": "https://asset-resources.gdevelop.io/public-resources/Icons/Glyphster Pack/Master/SVG/Computers and Hardware/3e5871434a72821bf3ecb44a6857e62a438cf23dc8f95966f56ae97e95315468_Computers and Hardware_keyboard.svg",
   "shortDescription": "3D car keyboard controls.",
   "version": "1.0.1",
-  "description": "3D physics car keyboard controls.",
+  "description": "3D physics car keyboard controls. Add this \"mapper\" behavior on the object having the 3D Physics Car behavior so that it's automatically controlled by the keyboard.",
   "origin": {
     "identifier": "PhysicsCharacter3DKeyMapper",
     "name": "gdevelop-extension-store"
@@ -243,4 +243,4 @@
     }
   ],
   "eventsBasedObjects": []
-}
+}