DevDocs corrections part 1

Started reviewing the developer docs, finding lots of things to correct. I'll do more later, but please review this batch first so I know what, if anything, needs to be fixed moving forward - I'm not entirely sure on the markdownish format used.
It seems to me that the appropriate thing to do is to allow this change and then, at some point in the future, create a pull adding a section to the docs (or some other page on the site) describing additional places devs can find help, such as the StackExchange.