Update usage.rst

[Ruijian-Zha]

Fix hyperlink format in .rst document

Corrected the syntax for the "terms" hyperlink in the reStructuredText file to adhere to .rst standards. This ensures proper rendering of the link in the documentation.

[sweep-ai-deprecated[bot]]

Apply Sweep Rules to your PR?

• [ ] Apply: Ensure all new functions and classes have very clear, concise and up-to-date docstrings. Take gpt_engineer/ai.py as a good example.

[TheoMcCabe]

Closing as the link is now outdated. Apologies this wasnt merged earlier - thanks for the contribution though.