Add the pass host header section to the services documentation

docs/content/routing/providers/docker.md

@@ -237,7 +237,8 @@ you'd add the label `traefik.http.services.<name-of-your-choice>.loadbalancer.pa
     ```
 
 ??? info "`traefik.http.services.<service_name>.loadbalancer.passhostheader`"
-    <!-- TODO doc passHostHeader in services page -->
+    
+    See [pass Host header](../services/index.md#pass-host-header) for more information.
     
     ```yaml
     - "traefik.http.services.myservice.loadbalancer.passhostheader=true"

docs/content/routing/providers/marathon.md

@@ -157,7 +157,8 @@ For example, to change the passHostHeader behavior, you'd add the label `"traefi
     ```
 
 ??? info "`traefik.http.services.<service_name>.loadbalancer.passhostheader`"
-    <!-- TODO doc passHostHeader in services page -->
+    
+    See [pass Host header](../services/index.md#pass-host-header) for more information.
     
     ```json
     "traefik.http.services.myservice.loadbalancer.passhostheader": "true"

docs/content/routing/providers/rancher.md

@@ -163,7 +163,8 @@ you'd add the label `traefik.http.services.{name-of-your-choice}.loadbalancer.pa
     ```
 
 ??? info "`traefik.http.services.<service_name>.loadbalancer.passhostheader`"
-    <!-- TODO doc passHostHeader in services page -->
+    
+    See [pass Host header](../services/index.md#pass-host-header) for more information.
     
     ```yaml
     - "traefik.http.services.myservice.loadbalancer.passhostheader=true"

docs/content/routing/services/index.md

@@ -322,6 +322,31 @@ Below are the available options for the health check mechanism:
                 My-Header: bar
     ```
 
+#### Pass Host Header
+
+The `passHostHeader` allows to forward client Host header to server.
+
+By default, `passHostHeader` is true.
+
+??? example "Don't forward the host header -- Using the [File Provider](../../providers/file.md)"
+
+    ```toml tab="TOML"
+    ## Dynamic configuration
+    [http.services]
+      [http.services.Service01]
+        [http.services.Service01.loadBalancer]
+          passHostHeader = false
+    ```
+    
+    ```yaml tab="YAML"
+    ## Dynamic configuration
+    http:
+      services:
+        Service01:
+          loadBalancer:
+            passHostHeader: false
+    ```
+
 ### Weighted Round Robin (service)
 
 The WRR is able to load balance the requests between multiple services based on weights.