Improving Clang-Doc

Clang-Doc is LLVM's modern C/C++ documentation generator built on the compiler AST rather than heuristic text parsing. A key blocker to its adoption is the absence of Markdown support inside documentation comments. Fenced code blocks, pipe tables, and lists currently pass through to output generators as raw text, making generated documentation unreadable for any project that uses Markdown in its comment workflow, which includes LLVM itself. This project implements a standalone Markdown parsing library that takes text and returns typed data structures, with no knowledge of comments or Clang internals. Clang-Doc is the immediate consumer, but the library is usable by any LLVM tool. It follows the same pattern as the Mustache library from GSoC 2024, with no third-party dependencies. Deliverables include the full library, Clang-Doc integration, updated HTML and Markdown generators, end-to-end lit/FileCheck tests, a libFuzzer harness, and an LLVM blog post. Stretch goal: Clang AST support for Doxygen group comments, flagged by mentors as particularly valuable.