Improvements to community documentation

I noticed that the Community Information & Contributing documentation page could be improved, so I made some improvements. Looking through the rest of the documentation, I couldn't find any consistency with regards to text-wrapping, so I used `fold` to wrap the file to 100 characters. Also, there are a few grammatical fixes, some phrasing alterations (generally made in order to maintain a more formal tone), and some sentences have been rearranged to improve the flow of the text.

The raw diff is a little messy due to the changes in text-wrapping, but GitHub's rendering of the rich diff makes the actual changes a lot clearer.