update plugins in docs and correct things in index.md

Signed-off-by: allencloud <allen.sun@daocloud.io>

docs/reference/commandline/events.md

@@ -36,7 +36,7 @@ Docker images report the following events:
 
     delete, import, load, pull, push, save, tag, untag
 
-Docker plugins(experimental) report the following events:
+Docker plugins report the following events:
 
     install, enable, disable, remove
 

docs/reference/commandline/index.md

@@ -165,4 +165,18 @@ read the [`dockerd`](dockerd.md) reference page.
 | [stack ls](stack_ls.md) | List stacks in the swarm                           |
 | [stack ps](stack_ps.md) | List the tasks in the stack                        |
 | [stack rm](stack_rm.md) | Remove the stack from the swarm                    |
-| [stack services](stack_services.md) | List the services in the stack         |
+| [stack services](stack_services.md) | List the services in the stack         |
+
+### Plugin commands
+
+| Command | Description                                                        |
+|:--------|:-------------------------------------------------------------------|
+| [plugin create](plugin_create.md) | Create a plugin from a rootfs and configuration |
+| [plugin disable](plugin_disable.md) | Disable a plugin                       |
+| [plugin enbale](plugin_enable.md)  | Enable a plugin                         |
+| [plugin inspect](plugin_inspect.md) | Display detailed information on a plugin |
+| [plugin install](plugin_install.md) | Install a plugin                       |
+| [plugin ls](plugin_ls.md) | List plugins                                     |
+| [plugin push](plugin_push.md) | Push a plugin to a registry                  |
+| [plugin rm](plugin_rm.md) | Remove a plugin                                  |
+| [plugin set](plugin_set.md)  | Change settings for a plugin                  |