revised API documentation

[mcfrank]

From Ian:

looking at the instructions on the analysis tab: users no longer need to generate an API token when working with R or Python, as they'll just get a popup window to sign in when relevant (generally a lot more user friendly). The only scenario where API tokens are required is when you're making API calls from a non-interactive session (like a server that makes regular calls to the Redivis API), which is definitely a more advanced / infrequent use case