Fix "AirDenstiy" typo in AtmosphereSensor (#890)

## Changes
Changed incorrect references to `AirDenstiy` in
`reference/engine/classes/AtmosphereSensor.yaml` to `AirDensity`.

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Author: dgxo

content/en-us/reference/engine/classes/AtmosphereSensor.yaml

@@ -4,12 +4,12 @@ category:
 memory_category: Instances
 summary: |
   A `Class.SensorBase` that outputs data about the
-  `Class.AtmosphereSensor.AirDenstiy|AirDenstiy` and
+  `Class.AtmosphereSensor.AirDensity|AirDensity` and
   `Class.AtmosphereSensor.RelativeWindVelocity|RelativeWindVelocity` at the
   sensor's position.
 description: |
   A `Class.SensorBase` that outputs data about the
-  `Class.AtmosphereSensor.AirDenstiy|AirDenstiy` and
+  `Class.AtmosphereSensor.AirDensity|AirDensity` and
   `Class.AtmosphereSensor.RelativeWindVelocity|RelativeWindVelocity` at the
   sensor's position.
 code_samples: []