Minor code improvements

[Asha20]

No description provided.

[arctic-hen7]

This is really great, thank you very much!

I'll say that the changes to ErrorPages don't constitute a breaking change because from looking at them I don't think they should break any user-facing code (and custom engines aren't supported yet), is that correct?

[arctic-hen7]

This seems to have some conflicts, are you able to resolve those?

[Asha20]

Alright, merge conflicts resolved.

Actually, I think this might be a breaking change because of the parameter type change from status: &u16 to status: u16; see this commit. Looking through the commit diff I see that I also had to update the parameters of files inside examples.

[arctic-hen7]

I genuinely have no clue why that comment was in italics, sometimes the GitHub mobile app is magical.

I don't see any changes to the parameters that examples take, I think they've always taken owned values haven't they?

[arctic-hen7]

If this isn't a breaking change, it's good to merge.

[arctic-hen7]

Yeah @Asha20 I'm pretty sure you've just needed to change some things in .perseus/ (which we work on inside examples/basic/, I know...), which doesn't constitute a breaking change.