Amend documentation

Author: kayman-mk

README.md

@@ -113,7 +113,7 @@ resource "aws_iam_service_linked_role" "autoscaling" {
 
 By default the runner is registered on initial deployment. In previous versions of this module this was a manual process. The manual process is still supported but will be removed in future releases. The runner token will be stored in the AWS SSM parameter store. See [example](examples/runner-pre-registered/) for more details.
 
-To register the runner automatically set the variable `gitlab_runner_registration_config["registration_token"]`. This token value can be found in your GitLab project, group, or global settings. For a generic runner you can find the token in the admin section. By default the runner will be locked to the target project, not run untagged. Below is an example of the configuration map.
+To register the runner automatically set the variable `gitlab_runner_registration_config["registration_token"]`. This token value can be found in your GitLab project, group, or global settings. For a generic runner you can find the token in the admin section. By default the runner will be locked to the target project, not run untagged. Below is an example of the configuration map. As this token should not appear in your source code management tool, use a SSM parameter which is set manually.
 
 ```hcl
 module "gitlab_runner" {