GHC Reading Guide

Dear devs, I've written a simple document about "GHC source reading" for myself and potential newcomers: * https://takenobu-hs.github.io/downloads/haskell_ghc_reading_guide.pdf (https://github.com/takenobu-hs/haskell-ghc-reading-guide) Please teach me if something's wrong. I'll learn and correct them. Happy Haskelling :) Regards, Takenobu