Adapt comments into RDoc convention

We already have an OK documentation present on the comments across the projects' files. This is fine, but RDoc pages are being generated with poorly formatted examples and some of the examples across the code are not being placed where it should.

This is very visible at our [Ability docs](https://www.rubydoc.info/gems/apicasso/0.4.11/Apicasso/Ability), which has fine examples, but they are very badly placed. Other examples are being poorly formatted, like the ones on the [CRUD Controller endpoints](https://www.rubydoc.info/gems/apicasso/0.4.11/Apicasso/CrudController).

This should be fixed for a better documentation.

Start by reviewing the comments rendered in the linked Ability docs and CRUD Controller endpoints, then locate their source comments in the repository. Compare the generated examples with RDoc conventions and verify that examples are correctly formatted and placed in the resulting documentation.

Written by the indexing model from the issue text.