impl Default for PreEscaped

[imbolc]

Tests was broken before the change, I'm not sure if I should fix them. But cargo test misc works.

[imbolc]

Also I noticed seemingly unnecessary type restriction:
struct PreEscaped<T: AsRef<str>>(pub T). I believe removing the AsRef restriction won't change any behavior, but it won't be necessary to repeat the restriction in each implementation. I can remove it in this PR if you'd like.

[lambda-fairy]

Thanks!

I believe removing the AsRef restriction won't change any behavior, but it won't be necessary to repeat the restriction in each implementation. I can remove it in this PR if you'd like.

That sounds like a good change. Though I'd prefer that in a separate PR, just to keep things small.

That reminds me, I should polish up #322 again...