Add pointer type covariance

[AutonomicPerfectionist]

Is this pull request associated with an issue(s)? No.

Description

This PR further enriches the type system by allowing pointer types to be checked for covariance. What this means is that a desc* can now be used where a str* is expected, whereas previously such a conversion would not be possible due to the invariant nature of the implementation. As such, pointer type inference has been enabled, meaning that the type system will be able to infer whether a string is a pointer and recursively dereferences and infers its type. So now, if we have:

set(a_ptr TRUE)
cpp_type_of(a_type a_ptr)

The value of ${a_type} will be bool* instead of desc like it would be previously. Additionally, bool* will now be convertible to str*

TODOs

• [x] Update documentation
• [x] Add new tests
• [x] Fix old tests

[github-actions[bot]]

🚀 [bumpr] Bumped! New version:v0.0.10 Changes:v0.0.9...v0.0.10

[ryanmrichard]

Unless I'm missing something, if this breaks CMaize or CMakeTests, it's probably those repose that need to change. Point being, I think we can merge this and deal with the fallout in other PRs.