<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=391035) </details> <!--IssueSummary end--> <!-- This template is a great use for issues that are feature::additions or technical tasks for larger issues.--> ### Proposal Right now GitLab (as of version 15.8) does not support syntax highlight for [heredocs](https://www.docker.com/blog/introduction-to-heredocs-in-dockerfiles/) in Dockerfiles. And it should :) For example, we are migrating from the classic format to "here document" and we no longer see syntax highlight for flags (like `-y` or `--no-install-recommends`) or shell variables (`${}`). Please take a look at the following screenshot:  <!-- Use this section to explain the feature and how it will work. It can be helpful to add technical details, design proposals, and links to related epics or issues. --> <!-- Consider adding related issues and epics to this issue. You can also reference the Feature Proposal Template (https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Feature%20proposal%20-%20detailed.md) for additional details to consider adding to this issue. Additionally, as a data oriented organization, when your feature exits planning breakdown, consider adding the `What does success look like, and how can we measure that?` section. --> <!-- Label reminders Use the following resources to find the appropriate labels: - Use only one tier label choosing the lowest tier this is intended for - https://gitlab.com/gitlab-org/gitlab/-/labels - https://about.gitlab.com/handbook/product/categories/features/ -->