Improve discoverability of environment variables documentation

[cwickham]

• Renames pages to distinguish between them:
  • "Project Environment Variables" — the _environment file
    feature. Keeps nav label as "Environment Variables" for brevity
  • "Quarto Environment Variables" — env vars Quarto reads/sets
• Adds callout to the project page linking to the Quarto env vars reference

Closes quarto-dev/quarto-cli#12896

[github-actions]

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🔄 Modified Documents

• docs/advanced/environment-vars.qmd
• docs/projects/environment.qmd

[cderv]

Callout is nice !

I wonder if we should have one for the other way.

Also did you consider listing the Quarto Environment variable page in

            - section: "Advanced"
              contents:
                - docs/authoring/includes.qmd
                - docs/authoring/variables.qmd
                - docs/output-formats/page-layout.qmd
                - docs/authoring/language.qmd
                - docs/authoring/conditional.qmd
                - docs/extensions/nbfilter.qmd
                - section: "Jupyter"
                  contents:
                    - docs/advanced/jupyter/kernel-execution.qmd

I think it could help too, but maybe you considered the callout would be enough. Which make sense in a way, but asking to confirm it was a choice.

[cwickham]

@cderv Yeah, we link in the text, but a callout might be more visible. It was intentional not to list in the Advanced section of the sidebar. I think I want to resurrect #1197, which separates the pages that are advanced authoring features (shortcodes, conditional content, etc.), from those that are docs for advanced use of Quarto beyond authoring .qmd (the things on https://quarto.org/docs/advanced/).

[cderv]

Make sense. Thanks !