Update Max/Nikhil bios and Max headshot

[MaxGhenis]

Fixes #726

🤖 Generated by Copilot at f160849

Summary

🖼️📝📚

Fixed image file extension and updated biographies for Max Ghenis and Nikhil Woodruff on the About page. Made minor formatting changes to authors.json.

Sing, O Muse, of the skillful pull request
That updated the About page with care
And fixed the image of Max, the adept
Economist, whose file extension was rare.

Walkthrough

• Change image file extension for Max Ghenis from jpg to png to match actual file format (link, link)
• Edit biography paragraphs for Nikhil Woodruff and Max Ghenis to use past tense for previous roles and improve clarity and conciseness in src/pages/AboutPage.jsx (link, link)
• Delete trailing newline at the end of src/posts/authors.json to comply with style guide or convention (link)