message: fix variable name in AREmission header
diff: @@ -42,7 +42,7 @@ NS_ASSUME_NONNULL_BEGIN
  gravityURL:(NSString *)gravity
  metaphysicsURL:(NSString *)metaphysics
  predictionURL:(NSString *)prediction
  - volleyURL:(NSString *)prediction
  + volleyURL:(NSString *)volleyURL
  userAgent:(NSString *)userAgent
  options:(NSDictionary *)options;
  @end
  