doc(instance_private_nic): added zone field doc & fix typo (scaleway#1328)

Co-authored-by: Rémy Léone <[email protected]>

Author: yfodil

docs/resources/instance_private_nic.md

@@ -9,7 +9,9 @@ description: |-
 Creates and manages Scaleway Instance Private NICs. For more information, see
 [the documentation](https://developers.scaleway.com/en/products/instance/api/#private-nics-a42eea).
 
-## Example
+## Examples
+
+### Basic
 
 ```hcl
 resource "scaleway_instance_private_nic" "pnic01" {
@@ -18,19 +20,41 @@ resource "scaleway_instance_private_nic" "pnic01" {
 }
 ```
 
+### With zone
+
+```hcl
+resource scaleway_vpc_private_network pn01 {
+  name = "private_network_instance"
+  zone = "fr-par-2"
+}
+
+resource "scaleway_instance_server" "base" {
+  image = "ubuntu_focal"
+  type  = "DEV1-S"
+  zone = scaleway_vpc_private_network.pn01.zone
+}
+
+resource "scaleway_instance_private_nic" "pnic01" {
+  server_id = scaleway_instance_server.base.id
+  private_network_id = scaleway_vpc_private_network.pn01.id
+  zone = scaleway_vpc_private_network.pn01.zone
+}
+```
+
 ## Arguments Reference
 
 The following arguments are required:
 
 - `server_id` - (Required) The ID of the server associated with.
 - `private_network_id` - (Required) The ID of the private network attached to.
+- `zone` - (Defaults to [provider](../index.md#zone) `zone`) The [zone](../guides/regions_and_zones.md#zones) in which the server must be created.
 
 ## Attributes Reference
 
 In addition to all above arguments, the following attributes are exported:
 
 - `id` - The ID of the private NIC.
-- ``mac_address` - The MAC address of the private NIC.
+- `mac_address` - The MAC address of the private NIC.
 
 ## Import