Clarify task placement docs

SoManyHs · SoManyHs · commit e43062dfb0e8 · 2018-08-21T16:23:37.000-07:00
diff --git a/README.md b/README.md
@@ -487,12 +487,12 @@ Currently, the only parameter supported under `run_params` is `network_configura
   * `assign_public_ip`: supported values for this field are either "ENABLED" or "DISABLED". This field is *only* used for tasks launched with Fargate launch type. If this field is present in tasks with network configuration launched with EC2 launch type, the request will fail.
 * `task_placement` is an optional field with `EC2` launch-type only (it is *not* valid for `FARGATE`). It has two subfields:
   * `strategy`: A list of objects, with two keys. Valid keys are `type` and `field`.
-    * `type`: Valid values are `random`, `binpack`, or `spread`. If `random` is specified, the `field` key is not necessary.
+    * `type`: Valid values are `random`, `binpack`, or `spread`. If `random` is specified, the `field` key should not be provided.
     * `field`: Valid values depend on the strategy type.
       * For `spread`, valid values are `instanceId`, `host`, or attribute key/value pairs, e.g. `attribute:ecs.instance-type =~ t2.*`
       * For "binpack", valid values are "cpu" or "memory".
   * `constraint`: A list of objects, with two keys. Valid keys are `type` and `expression`.
-    * `type`: Valid values are `distinctInstance` and `memberOf`. If `distinctInstance` is specified, the `expression key is not necessary.
+    * `type`: Valid values are `distinctInstance` and `memberOf`. If `distinctInstance` is specified, the `expression` key should not be provided.
     * `expression`: When `type` is `memberOf`, valid values are key/value pairs for attributes or task groups, e.g. `task:group == databases` or `attribute:color =~ green`.
 
 For more information on task placement, see [Amazon ECS TaskPlacement] (https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-placement.html).
