Resolve Duplicate Docs Warnings

[jherdman]

Warnings were being issued regarding duplicate documentation
declarations. Here's an example:

warning: redefining @doc attribute previously set at line 27.

Please remove the duplicate docs. If instead you want to override a previously defined @doc, attach the @doc attribute to a function head (the function signature not followed by any do-block). For example:

    @doc """
    new docs
    """
    def use_cassette(...)

  lib/exvcr/mock.ex:48: ExVCR.Mock.use_cassette/3

This change resolves these warnings by merging documentation and adding
examples that were already available in the README file.

[xn]

Is there any reason this can't be merged?

[parroty]

Thank you for the follow up. Sorry being late to respond 🙇 . I was overlooking this item.