docs/resource/aws_autoscaling_policy: Add missing min_adjustment_magn…

…itude argument (#14807)

* missing min_adjustment_magnitude argument in the docs

* Update website/docs/r/autoscaling_policy.html.markdown

Co-authored-by: Brian Flad <bflad417@gmail.com>

Co-authored-by: Brian Flad <bflad417@gmail.com>

website/docs/r/autoscaling_policy.html.markdown

@@ -49,6 +49,10 @@ The following arguments are supported:
 * `policy_type` - (Optional) The policy type, either "SimpleScaling", "StepScaling" or "TargetTrackingScaling". If this value isn't provided, AWS will default to "SimpleScaling."
 * `estimated_instance_warmup` - (Optional) The estimated time, in seconds, until a newly launched instance will contribute CloudWatch metrics. Without a value, AWS will default to the group's specified cooldown period.
 
+The following argument is only available to "SimpleScaling" and "StepScaling" type policies:
+
+* `min_adjustment_magnitude` - (Optional) Minimum value to scale by when `adjustment_type` is set to `PercentChangeInCapacity`.
+
 The following arguments are only available to "SimpleScaling" type policies:
 
 * `cooldown` - (Optional) The amount of time, in seconds, after a scaling activity completes and before the next scaling activity can start.