The Open edX Contributor's Guide needs some proofreading!

Hi devs! :wave: @andres has kickstarted an effort to document his journey as a fledgling Open edX contributor:

It would be great if more seasoned developers could have a look at this and collaboratively add content there. :eyes: @jmbowman @nimisha @feanil maybe? Everyone should feel free to hack at it, in a wiki kind of way. Then this document could be published or migrated to the official docs.