Add more examples to docs

[Technologicat]

The documentation could use more code examples of how to use the various features of mcpyrate. Each item should include the actual code example, an explanation of what is it for and what it does, and if applicable, the output printed by the example.

Particularly, the mcpyrate.debug.step_expansion macro would be nice to showcase in a more detailed manner.

But basically anything in the public API (i.e. in the magic __all__ of any module) could be demonstrated, starting with the most important tools.

There's a certain balance to keep here - documenting every last detail may lead to software ossification. Minute details belong in docstrings; the documentation should explain the main points and aid the discoverability of features.