added-yang-linter-and-resolved-all-error-produced-by it

Change-Id: Iba95a07bb1ed6230b9a900448bf294355a58285c
diff --git a/config-models/aether-2.2.x/files/yang/service-group.yang b/config-models/aether-2.2.x/files/yang/service-group.yang
index 9f2e7da..bb5ddf2 100755
--- a/config-models/aether-2.2.x/files/yang/service-group.yang
+++ b/config-models/aether-2.2.x/files/yang/service-group.yang
@@ -23,6 +23,7 @@
         type string {
             length 1..32;
         }
+    description "The typedef for service-group-id";
   }
 
   typedef service-kind {
@@ -30,6 +31,7 @@
       length 1..32;
       pattern "default|on-demand";
     }
+    description "The typedef for service-kind";
   }
 
   container service-group {
@@ -61,20 +63,21 @@
           description
               "Link to service policy";
         }
-        leaf kind {    
+        leaf kind {
           type service-kind;
           default "default";
           description
             "Type of service link";
         }
-      }      
+        description "The list for service-policies";
+      }
 
       leaf description {
         type string {
           length 1..100;
         }
         description "description of this service group";
-      }      
+      }
     }
-  } 
+  }
 }