Adds a new docs website, built with Gatsby JS, to replace the old Jekyll site. Source code for the new site lives in /www (although markdown and YML data still comes from the legacy /docs folder).
Changes to either markdown or website source code can be previewed on Netlify. The react-js bot should automatically add comments to each PR with preview links. (This preview is generated by running the newly-added yarn build:docs command in the root package.json.)
The majority of the changes in this PR are contained within the new /www directory. However some minor modifications have been made to existing content in the /docs directory:
* Modified frontmatter author block to always be an array
* Small markdown formatting tweaks
My first contribution to React!
While upgrading a React project, I found some suspect SVG that needed updating, so I dug in after checking the docs. I knew that support for some SVG properties had been added (namely `xmlns` and `xmlnsXlink`), but I noticed them missing from the reference's attribute list. This pull request updates `reference-dom-elements.md` by adding said properties.