Include cd command for building ReadTheDocs locally

[bvandermoon]

Description

Minor change to make RTD local build commands work fully with copy/paste. Adding the cd command to the proper directory in sphinx-build step

Tests

Built RTD locally and ran the commands with copy/paste

Checklist

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• 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.