Improve providers documentation.

docs/content/providers/kubernetes-crd.md

@@ -19,6 +19,23 @@ we ended up writing a [Custom Resource Definition](https://kubernetes.io/docs/co
 
 _Optional, Default=empty_
 
+```toml tab="File (TOML)"
+[providers.kubernetesCRD]
+  endpoint = "http://localhost:8080"
+  # ...
+```
+
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    endpoint = "http://localhost:8080"
+    # ...
+```
+
+```bash tab="CLI"
+--providers.kubernetescrd.endpoint="http://localhost:8080"
+```
+
 The Kubernetes server endpoint as URL.
 
 When deployed into Kubernetes, Traefik will read the environment variables `KUBERNETES_SERVICE_HOST` and `KUBERNETES_SERVICE_PORT` or `KUBECONFIG` to construct the endpoint.
@@ -32,109 +49,130 @@ When the environment variables are not found, Traefik will try to connect to the
 In this case, the endpoint is required.
 Specifically, it may be set to the URL used by `kubectl proxy` to connect to a Kubernetes cluster using the granted authentication and authorization of the associated kubeconfig.
 
-```toml tab="File"
-[providers.kubernetesCRD]
-  endpoint = "http://localhost:8080"
-  # ...
-```
-
-```txt tab="CLI"
---providers.kubernetescrd
---providers.kubernetescrd.endpoint="http://localhost:8080"
-```
-
 ### `token`
 
 _Optional, Default=empty_
 
-Bearer token used for the Kubernetes client configuration.
-
-```toml tab="File"
+```toml tab="File (TOML)"
 [providers.kubernetesCRD]
   token = "mytoken"
   # ...
 ```
 
-```txt tab="CLI"
---providers.kubernetescrd
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    token = "mytoken"
+    # ...
+```
+
+```bash tab="CLI"
 --providers.kubernetescrd.token="mytoken"
 ```
 
+Bearer token used for the Kubernetes client configuration.
+
 ### `certAuthFilePath`
 
 _Optional, Default=empty_
 
-Path to the certificate authority file.
-Used for the Kubernetes client configuration.
-
-```toml tab="File"
+```toml tab="File (TOML)"
 [providers.kubernetesCRD]
   certAuthFilePath = "/my/ca.crt"
   # ...
 ```
 
-```txt tab="CLI"
---providers.kubernetescrd
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    certAuthFilePath: "/my/ca.crt"
+    # ...
+```
+
+```bash tab="CLI"
 --providers.kubernetescrd.certauthfilepath="/my/ca.crt"
 ```
 
+Path to the certificate authority file.
+Used for the Kubernetes client configuration.
+
 ### `namespaces`
 
 _Optional, Default: all namespaces (empty array)_
 
-Array of namespaces to watch.
-
-```toml tab="File"
+```toml tab="File (TOML)"
 [providers.kubernetesCRD]
   namespaces = ["default", "production"]
   # ...
 ```
 
-```txt tab="CLI"
---providers.kubernetescrd
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    namespaces:
+    - "default"
+    - "production"
+    # ...
+```
+
+```bash tab="CLI"
 --providers.kubernetescrd.namespaces="default,production"
 ```
 
+Array of namespaces to watch.
+
 ### `labelselector`
 
 _Optional,Default: empty (process all Ingresses)_
 
+```toml tab="File (TOML)"
+[providers.kubernetesCRD]
+  labelselector = "A and not B"
+  # ...
+```
+
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    labelselector: "A and not B"
+    # ...
+```
+
+```bash tab="CLI"
+--providers.kubernetescrd.labelselector="A and not B"
+```
+
 By default, Traefik processes all Ingress objects in the configured namespaces.
 A label selector can be defined to filter on specific Ingress objects only.
 
 See [label-selectors](https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors) for details.
 
-```toml tab="File"
-[providers.kubernetesCRD]
-  labelselector = "A and not B"
-  # ...
-```
-
-```txt tab="CLI"
---providers.kubernetescrd
---providers.kubernetescrd.labelselector="A and not B"
-```
-
 ### `ingressClass`
 
 _Optional, Default: empty_
 
-Value of `kubernetes.io/ingress.class` annotation that identifies Ingress objects to be processed.
-
-If the parameter is non-empty, only Ingresses containing an annotation with the same value are processed.
-Otherwise, Ingresses missing the annotation, having an empty value, or the value `traefik` are processed.
-
-```toml tab="File"
+```toml tab="File (TOML)"
 [providers.kubernetesCRD]
   ingressClass = "traefik-internal"
   # ...
 ```
 
-```txt tab="CLI"
---providers.kubernetescrd
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    ingressClass: "traefik-internal"
+    # ...
+```
+
+```bash tab="CLI"
 --providers.kubernetescrd.ingressclass="traefik-internal"
 ```
 
+Value of `kubernetes.io/ingress.class` annotation that identifies Ingress objects to be processed.
+
+If the parameter is non-empty, only Ingresses containing an annotation with the same value are processed.
+Otherwise, Ingresses missing the annotation, having an empty value, or the value `traefik` are processed.
+
 ## Resource Configuration
 
 If you're in a hurry, maybe you'd rather go through the [dynamic](../reference/dynamic-configuration/kubernetes-crd.md) configuration reference.