Cross-linking between compose and configs/secrets (#4869)

compose/compose-file/index.md

@@ -350,6 +350,8 @@ configuration. Two different syntax variants are supported.
 > [defined in the top-level `configs` configuration](#configs-configuration-reference)
 > of this stack file, or stack deployment will fail.
 
+For more information on configs, see [configs](/engine/swarm/configs.md).
+
 #### Short syntax
 
 The short syntax variant only specifies the config name. This grants the
@@ -1372,6 +1374,8 @@ configuration. Two different syntax variants are supported.
 > [defined in the top-level `secrets` configuration](#secrets-configuration-reference)
 > of this stack file, or stack deployment will fail.
 
+For more information on secrets, see [secrets](/engine/swarm/secrets.md).
+
 #### Short syntax
 
 The short syntax variant only specifies the secret name. This grants the

engine/swarm/configs.md

@@ -80,6 +80,12 @@ Docker configs.
 > simplicity. The examples use Linux containers, but Windows containers also
 > support configs.
 
+### Defining and using configs in compose files
+
+Both the `docker compose` and `docker stack` commands support defining configs
+in a compose file. See
+[the Compose file reference](/compose/compose-file/#configs) for details.
+
 ### Simple example: Get started with configs
 
 This simple example shows how configs work in just a few commands. For a
@@ -147,7 +153,7 @@ real-world example, continue to
     $ docker config rm my-config
 
     Error response from daemon: rpc error: code = 3 desc = config 'my-config' is
-    in use by the following service: redis 
+    in use by the following service: redis
     ```
 
 6.  Remove access to the config from the running `redis` service by updating the
@@ -214,7 +220,7 @@ This example assumes that you have PowerShell installed.
         --config src=homepage,target="\inetpub\wwwroot\index.html"
         microsoft/iis:nanoserver  
     ```
- 
+
 5.  Access the IIS service at `http://localhost:8000/`. It should serve
     the HTML content from the first step.
 

engine/swarm/secrets.md

@@ -143,6 +143,12 @@ a similar way, see
 > support secrets in Docker 17.06 and higher.
 > See [Windows support](#windows-support).
 
+### Defining and using secrets in compose files
+
+Both the `docker compose` and `docker stack` commands support defining secrets
+in a compose file. See
+[the Compose file reference](/compose/compose-file/#secrets) for details.
+
 ### Simple example: Get started with secrets
 
 This simple example shows how secrets work in just a few commands. For a