Repository: traefik/traefik (language: go)

Issue:
3.0 - Docker / Swarm provider: SwarmMode key still documented
### Welcome!

- [X] Yes, I've searched similar issues on [GitHub](https://github.com/traefik/traefik/issues) and didn't find any.
- [X] Yes, I've searched similar issues on the [Traefik community forum](https://community.traefik.io) and didn't find any.

### What did you do?

From the Docs: [swarmMode](https://doc.traefik.io/traefik/v3.0/providers/swarm/#swarmmode)

Optional, Default=false

Enables the Swarm Mode (instead of standalone Docker).

```toml
[providers.swarm]
  swarmMode = true
  # ...
```

This is redundant; the swarm provider is _always_ in swarmMode (and I believe the swarmMode key was removed altogether in beta3). I suspect this was overlooked when it was pulled out of the docker provider.

### What did you see instead?

```
{"level":"error","error":"command traefik error: field not found, node: swarmMode","time":"2023-07-01T23:43:35Z","message":"Command error"}
```

### What version of Traefik are you using?

3.0.0-beta3

### What is your environment & configuration?

```toml
[providers]
  [providers.swarm]
    # swarm classic (1.12-)
    # endpoint = "tcp://127.0.0.1:2375"
    # docker swarm mode (1.12+)
    endpoint = "tcp://127.0.0.1:2377"
    exposedByDefault = false
    network = "traefik-network"
    # This is a legacy value that I expect to disappear shortly; the swarm provider should _always_ be in swarmmode.
    swarmMode = true
```

### If applicable, please paste the log output in DEBUG level

_No response_


Discussion / hints:

Fix patch:
diff --git a/docs/content/providers/swarm.md b/docs/content/providers/swarm.md
index 96c987c876..4165832812 100644
--- a/docs/content/providers/swarm.md
+++ b/docs/content/providers/swarm.md
@@ -407,31 +407,7 @@ providers:
 # ...
 ```
 
-### `swarmMode`
-
-_Optional, Default=false_
-
-Enables the Swarm Mode (instead of standalone Docker).
-
-```yaml tab="File (YAML)"
-providers:
-  swarm:
-    swarmMode: true
-    # ...
-```
-
-```toml tab="File (TOML)"
-[providers.swarm]
-  swarmMode = true
-  # ...
-```
-
-```bash tab="CLI"
---providers.swarm.swarmMode=true
-# ...
-```
-
-### `swarmModeRefreshSeconds`
+### `refreshSeconds`
 
 _Optional, Default=15_
 
@@ -440,18 +416,18 @@ Defines the polling interval (in seconds) for Swarm Mode.
 ```yaml tab="File (YAML)"
 providers:
   swarm:
-    swarmModeRefreshSeconds: 30
+    refreshSeconds: 30
     # ...
 ```
 
 ```toml tab="File (TOML)"
 [providers.swarm]
-  swarmModeRefreshSeconds = 30
+  refreshSeconds = 30
   # ...
 ```
 
 ```bash tab="CLI"
---providers.swarm.swarmModeRefreshSeconds=30
+--providers.swarm.refreshSeconds=30
 # ...
 ```
 


Test patch: