better support for dynamic docs

[UnquietCode]

relates to #40

• [ ] remove 'dynamic documentation' return string

• [ ] add method parameter docs

  • captures either a string or a callable
  • (turn strings into callables)

• [ ] add annotation @with_docs which takes a similar arguments

  • string or callable as sole argument
  • annotation must be imported from another module, not in the immediate namespace
  • ensure decorated steps are still able to be located within the class

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  ☀ This issue was created by email; some cleanup may be required.