Justin Hileman refreshed the Notebooks documentation in the DataDog/documentation repository, focusing on improving clarity for users building diagrams with Mermaid.js. He consolidated guidance on using Markdown cells, detailing both the /markdown shortcut and Add Cell menu, and overhauled terminology by replacing references to 'cells' with 'documents' and 'content.' This update also included notes on text tables and public API changes to ensure accuracy. Justin applied his skills in technical writing and documentation, working exclusively in Markdown. The work addressed user confusion, aiming to reduce onboarding time and support queries, and was delivered through two targeted documentation commits.