Based on a discussion with Carlos and Rob on a PR related to the php runtime I reorganized and split our docs introducing actions (create, invoke) and the language specific parts.
I’m working up toward adding a doc that describes how to add a new runtime (and refactoring of the tests to also provide some parity and commonality). PR: https://github.com/apache/incubator-openwhisk/pull/3816 And link to new action doc directly: https://github.com/rabbah/openwhisk/blob/7b51dc6cb03af70c4aeba51faa6004c91f840f89/docs/actions.md -r
