Add underscore to variable name pull_policy for consistency

doc/user/application_security/sast/index.md

@@ -936,7 +936,7 @@ To use SAST in an offline environment, you need:
 - A Docker Container Registry with locally available copies of SAST [analyzer](https://gitlab.com/gitlab-org/security-products/analyzers) images.
 - Configure certificate checking of packages (optional).
 
-GitLab Runner has a [default `pull policy` of `always`](https://docs.gitlab.com/runner/executors/docker.html#using-the-always-pull-policy),
+GitLab Runner has a [default `pull_policy` of `always`](https://docs.gitlab.com/runner/executors/docker.html#using-the-always-pull-policy),
 meaning the runner tries to pull Docker images from the GitLab container registry even if a local
 copy is available. The GitLab Runner [`pull_policy` can be set to `if-not-present`](https://docs.gitlab.com/runner/executors/docker.html#using-the-if-not-present-pull-policy)
 in an offline environment if you prefer using only locally available Docker images. However, we