Style fixes

[samueltardieu]

Apply various style fixes found by Clippy:

• Do not deconstruct an error to rebuild it right after
• Remove useless as usize
• Use char rather than &str as starts_with() argument
• Remove useless references

[samueltardieu]

I have separated the style fixes into various commits so that some could be removed if the maintainers prefer to let the code this way. This can be the case for the "Remove useless as usize" for example, as even though I don't find !0 as usize more readable than !0 (or usize::MAX as I would have used myself), some others may differ.

[samueltardieu]

Rebased on current master branch.

[samueltardieu]

Is this a real failure? MacOS jobs just display "This job failed" without any info, did the jobs start?

[tgross35]

@samueltardieu could you rebase this? I think the CI failures were just since GH disabled the old MacOS runners, this repo hasn't had maintenance in a little while.

(or usize::MAX as I would have used myself)

+1, could you change !0 to type::MAX?

[tgross35]

There are also a few new failures as reported in #153, feel free to fix those as well then we can check Clippy in CI.

[samueltardieu]

Done. I've also added new fixes in separate commits.

[tgross35]

Ah I guess MSRV is the reason MAX isn't used. Hopefully we can increase this soon, but for now I suppose could you leave this as !0usize with // FIXME(msrv): use `usize::MAX` when available?

[tgross35]

Thanks for the quick updates!