fix broken link

Signed-off-by: Victor Vieux <vieux@docker.com>

docs/extend/menu.md

@@ -17,3 +17,4 @@ weight = 0
 Currently, you can extend Docker Engine by adding a plugin. This section contains the following topics:
 
 * [Understand Docker plugins](plugins.md)
+* [Write a volume plugin](plugins_volume.md)

docs/extend/plugins.md

@@ -97,7 +97,7 @@ started without error.
     <content of /remote on machine 1.2.3.4>
     ```
 
-5. Verify the plugin successfully crated the volume.
+5. Verify the plugin successfully created the volume.
 
     ```bash
     $ docker volume ls
@@ -109,7 +109,7 @@ started without error.
     You can stop a plugin with the `docker plugin disable`
     command or remove a plugin with `docker plugin remove`.
 
-See the [command line reference](../engine/reference/commandline/) for more
+See the [command line reference](../reference/commandline/index.md) for more
 information.
 
 ## How to develop a plugin

docs/extend/plugins_volume.md

@@ -11,10 +11,6 @@ weight=6
 
 # Write a volume plugin
 
-This document describes Docker Engine volume plugins generally available in
-Docker Engine 1.12 and earlier. To view information on plugins managed by Docker
-Engine, refer to [Docker Engine plugin system](plugins.md).
-
 Docker Engine volume plugins enable Engine deployments to be integrated with
 external storage systems, such as Amazon EBS, and enable data volumes to persist
 beyond the lifetime of a single Engine host. See the [plugin

docs/userguide/networking/index.md

@@ -537,7 +537,7 @@ built-in network drivers. For example:
 You can inspect it, add containers to and from it, and so forth. Of course,
 different plugins may make use of different technologies or frameworks. Custom
 networks can include features not present in Docker's default networks. For more
-information on writing plugins, see [Extending Docker](../../extend/index.md) and
+information on writing plugins, see [Extending Docker](../../extend/plugins.md) and
 [Writing a network driver plugin](../../extend/plugins_network.md).
 
 ### Docker embedded DNS server