[app-config] Update descriptions of the properties (Azure#22701)

* Update descriptions of the properties

* update description based on comment

Author: minhanh-phan

specification/appconfiguration/data-plane/Microsoft.AppConfiguration/preview/2022-11-01-preview/appconfiguration.json

@@ -180,7 +180,7 @@
           {
             "name": "snapshot",
             "in": "query",
-            "description": "A filter used get key-values for a snapshot. Not valid when used with 'key' and 'label' filters.",
+            "description": "A filter used get key-values for a snapshot. The value should be the name of the snapshot. Not valid when used with 'key' and 'label' filters.",
             "type": "string"
           }
         ],
@@ -926,7 +926,7 @@
           {
             "name": "name",
             "in": "path",
-            "description": "The name of the key-value snapshot to delete.",
+            "description": "The name of the key-value snapshot to update.",
             "required": true,
             "type": "string"
           },