anchor.diff:  --------------------------------------------------
   // CONSOLE
   
  -Or:
  +This update is transient:
   
   [source,js]
   --------------------------------------------------
  
positive.code: --------------------------------------------------
  // TESTRESPONSE[s/\.\.\./"acknowledged": true,/]
  
  Resetting persistent or transient settings can be done by assigning a
  `null` value. If a transient setting is reset, the persistent setting
  is applied if available. Otherwise Elasticsearch will fallback to the setting
  defined at the configuration file or, if not existent, to the default
  value. Here is an example:
  
  [source,js]
  --------------------------------------------------
  
negative.code: [[cluster-update-settings]]
  == Cluster Update Settings
  
  Use this API to review and change cluster-wide settings. 
  
  To review cluster settings:
  
  [source,js]
  --------------------------------------------------
  GET /_cluster/settings
  --------------------------------------------------
  // CONSOLE
  
  Updates to settings can be persistent, meaning they apply across restarts, or transient, where they don't 
  survive a full cluster restart. Here is an example of a persistent update:
  
  [source,js]
  --------------------------------------------------
  