[exersizes/conversions/as_ref_mut.rs] Why should I want to use AsRef / AsMut

[TheLarkInn]

As a first time rust learner, after the as_ref_mut.rs lesson, I was left curious why AsRef or AsMut are valuable tools. Typically I look for a hint to provide these answers, however the hint is pretty lacking here:

Feature Request: Please provide a more elaborate explanation as to why AsRef or AsMut are so valueable, and why I would need to use them. Additionally, perhaps provide more unit tests also showcasing why I would want to use these two impls/methods.

(Just finished rustlings and really appreciate the work everyone has done on it! 🎉 💯 )

[TheLarkInn]

Also after reading #404, I think this could serve as the literature for updating the lesson.

[shadows-withal]

Good point, there's a couple of issues relating to this exercise (or set of exercises now), so I'll look at it when I have time 👍