metrics-addr is not experimental since 20.10²

Missed the last paragraph, sorry

Author: u1735067

docs/reference/commandline/dockerd.md

@@ -904,10 +904,6 @@ scrape_configs:
       - targets: ['127.0.0.1:9323']
 ```
 
-Please note that this feature is still marked as experimental as metrics and metric
-names could change while this feature is still in experimental.  Please provide
-feedback on what you would like to see collected in the API.
-
 #### Node Generic Resources
 
 The `--node-generic-resources` option takes a list of key-value