Merge pull request #8515 from mpeters/ec2_group_state_doc_fix

Small doc addition to ec2_group to show the various values for "state"

library/cloud/ec2_group

@@ -40,9 +40,10 @@ options:
   state:
     version_added: "1.4"
     description:
-      - create or delete security group
+      - Create or delete a security group
     required: false
     default: 'present'
+    choices: [ "present", "absent" ]
     aliases: []
 
 extends_documentation_fragment: aws