Jacoguzo/tutorials editable code

[jacoguzo]

Description

FIXES: b/463397633

Issue: Customers may prefer for a command they can edit rather than writing in one by one as it is currently set up in Step 4 in the maxtext read the docs. The documentation should provide a template command they can edit/copy-paste rather than forcing them to construct it one by one.

This PR changes all env variable blocks in the tutorials to have editable text.

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Tests

Please describe how you tested this change, and include any instructions and/or
commands to reproduce.

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code. For an optional AI review, add the gemini-review label.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run end-to-end tests tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed, including adding new documentation pages to the relevant Table of Contents (toctree directive) as explained in our documentation.

[melissawm]

This looks good, I'm not a javascript expert but the built docs look and work correctly. Nice @jacoguzo !

[SurbhiJainUSC]

This looks good, I'm not a javascript expert but the built docs look and work correctly. Nice @jacoguzo !

Where can I see an example of the doc build with this change?