Add Screenshot workflow

In a few places in the docs, it would be really nice to be able to run some code take a screen shot, and draw boxes around different parts. For example setup an example click app with multiple sub commands, options, epilog help, and arguments and then draw boxes and label the various blocks. Requirements:

• run locally for doc generation (actually locally not calling out to api)
• run in ci job (not calling out to external service)
• No added dependencies that are not pip installable
• have the screen shots not be blurry (common problem)
• draw boxes around various sections.

Conduct some research and propose some options. A maintainer will pick from the options. and you can implement it. Here is an example of what I was thinking is in the comments below.

Start by researching locally runnable, pip-installable options for generating sharp screenshots and annotating CLI documentation examples, including execution in CI without external services. Use the stated requirements to compare the options and propose them to a maintainer; the research is complete when one option is selected for implementation.