As an AI language model, I don't have personal experience with Microsoft Loop, but according to the official Microsoft Loop documentation, it is a collaborative workspace for planning and tracking projects, and supports markdown syntax for formatting text.
Markdown syntax allows for easy and flexible formatting of text, but it does not support code blocks or syntax highlighting natively. However, it is possible to embed code snippets within markdown using inline code formatting (backticks ```), or by using third-party apps or plugins to add code block functionality. Some examples of apps that support code blocks in Microsoft Loop include Code Snippet and Embed Code Block.