fix the documentation about middleware labels.

docs/content/middlewares/overview.md

@@ -123,7 +123,7 @@ If you use multiple `providers` and wish to reference a middleware declared in a
 
         labels:
           # Attach file.add-foo-prefix middleware (declared in file)
-          - "traefik.http.routers.middlewares=file.add-foo-prefix"
+          - "traefik.http.routers.my-container.middlewares=file.add-foo-prefix"
     ```
 
 ## Available Middlewares

docs/content/providers/docker.md

@@ -248,7 +248,7 @@ You can declare pieces of middleware using labels starting with `traefik.http.mi
            # ...
            labels:
              - traefik.http.middlewares.my-redirect.schemeredirect.scheme=https
-             - traefik.http.routers.middlewares=my-redirect
+             - traefik.http.routers.my-container.middlewares=my-redirect
     ```
 
 !!! warning "Conflicts in Declaration"

docs/content/providers/marathon.md

@@ -278,7 +278,7 @@ For example, to declare a middleware [`schemeredirect`](../middlewares/redirects
 		...
 		"labels": {
 			"traefik.http.middlewares.my-redirect.schemeredirect.scheme": "https",
-			"traefik.http.routers.middlewares": "my-redirect"
+			"traefik.http.routers.my-container.middlewares": "my-redirect"
 		}
 	}
     ```

docs/content/providers/rancher.md

@@ -163,7 +163,7 @@ For example, to declare a middleware [`schemeredirect`](../middlewares/redirects
     # ...
     labels:
      - traefik.http.middlewares.my-redirect.schemeredirect.scheme=https
-     - traefik.http.routers.middlewares=my-redirect
+     - traefik.http.routers.my-container.middlewares=my-redirect
     ```
 
 !!! warning "Conflicts in Declaration"