docs: Add `hexo-prism-plus` to enable Prism syntax highlighting. (#870)
docs: Add `hexo-prism-plus` to enable Prism syntax highlighting. (#870)

The default syntax highlighting provided by Hexo uses highlight.js.  While
there are a number of great syntax highlights provided by highlight.js, some of
the more important ones to the Apollo project: `graphql`, `typescript`, and
`jsx` are notably missing.

This uses the `hexo-prism-plus` plugin for Hexo, along with some upstream
configuration to `apollo-hexo-config`[0] and `meteor-theme-hexo` (previously
named `hexo-theme-meteor`)[1].  See refs for more information!

[0] https://github.com/apollographql/apollo-hexo-config/commit/547107b0
[1] https://github.com/meteor/meteor-theme-hexo/pull/61
apollostack/apollo-android,apollostack/apollo-android,apollostack/apollo-android,apollographql/apollo-android,apollographql/apollo-android,apollographql/apollo-android