Fix some minor typos

Created by: kammoh

Hi! Here are some minor typos I noticed while skimming through the specs. The PR also includes changes to markdown table to fix a couple of formatting issues and make easier to follow when reading/editing in a text-only mode. It also adds sv language identifier for proper highlighting of in-lined SystemVerilog code (It should work with GitHub markdown, as well many other editors and tools supporting the GitHub dialect). Hope it's gonna be useful :) Thanks for the great work!