[Chapel Merge] Add a bunch of notes to README

Branch: refs/heads/main
Revision: 608c941
Author: bradcray
Log Message:

Merge pull request #2 from bradcray/flesh-out-readme

Add a bunch of notes to README

Add some notes about how to use the Chapel mode to the README.

Modified Files:
M README.md

Compare: https://github.com/chapel-lang/highlightjs-chapel/compare/e4e5c4c59bca...608c94140662