Enable some clippy lints

[pczarn]

No description provided.

[pczarn]

@Jujumba Could you review this? Any ideas on this?

[pczarn]

We might find some more Clippy lints fit for our projects. They do run in the CI.

Thanks in advance.

[Jujumba]

Looks good, but I personally use variable shadowing from time to time, so not quite sure how this will affect future contributions. Perhaps we should write CONTRIBUTIONS.md guide, or whatever?

[Jujumba]

I propose we also apply the following lints:

• cllippy::single_match

Checks for matches with a single arm where an if let will usually suffice.

• clippy::missing_safety_doc

Suggests the use of const in functions and methods where possible.

• clippy::missing_const_for_fn

Suggests the use of const in functions and methods where possible.

@pczarn

[pczarn]

Also

multiple_bound_locations ¶ 📋
suspicious warn
What it does

Check if a generic is defined both in the bound predicate and in the where clause.

multiple_inherent_impl

[pczarn]

The const fn lint should not be used on stable. We're working on stable.