Merge branch 'add-gitlab-pages-headers-example' into 'master'

Add GitLab pages headers example

See merge request gitlab-org/gitlab!55890

doc/administration/pages/index.md

@@ -239,7 +239,7 @@ control over how the Pages daemon runs and serves content in your environment.
 | `gitlab_secret`                         | The OAuth application secret. Leave blank to automatically fill when Pages authenticates with GitLab. |
 | `auth_scope`                            | The OAuth application scope to use for authentication. Must match GitLab Pages OAuth application settings. Leave blank to use `api` scope by default. |
 | `gitlab_server`                         | Server to use for authentication when access control is enabled; defaults to GitLab `external_url`. |
-| `headers`                               | Specify any additional http headers that should be sent to the client with each response. |
+| `headers`                               | Specify any additional http headers that should be sent to the client with each response. Multiple headers can be given as an array, header and value as one string, for example `['my-header: myvalue', 'my-other-header: my-other-value']` |
 | `inplace_chroot`                        | On [systems that don't support bind-mounts](index.md#additional-configuration-for-docker-container), this instructs GitLab Pages to `chroot` into its `pages_path` directory. Some caveats exist when using in-place `chroot`; refer to the GitLab Pages [README](https://gitlab.com/gitlab-org/gitlab-pages/blob/master/README.md#caveats) for more information. |
 | `insecure_ciphers`                      | Use default list of cipher suites, may contain insecure ones like 3DES and RC4. |
 | `internal_gitlab_server`                | Internal GitLab server address used exclusively for API requests. Useful if you want to send that traffic over an internal load balancer. Defaults to GitLab `external_url`. |