Documentation: Differences with GraphiQL

[kimobrian]

This issue pertains to the following package(s):

• GraphQL Playground vs GraphiQL Docs

An update to the documentation will be necessary regarding the features that it provides that are not in GraphiQL. Check out the GraphiQL Electron app which provides all the features outlined as differences in this README. The GraphiQL browser version also provides Query history.

[jedahan]

Also features that are not provided, like passing a query inside query parameters - graphiql supports this, while graphql-playground does not.