Typo fixes

[awaitlink]

Fixes various typos.

[awaitlink]

@Centril Perhaps this can be re-phrased? I can't seem to understand what the except that they do not meet... part means. Does that mean except if they or except then they...

[Centril]

Consider:

struct A<T>(T);

unsafe impl<T: Copy> Send for A<T> {}

fn assert_send<T: Send>() {}

fn main() {
    assert_send::<A<u8>>();
    assert_send::<A<String>>();
}

[awaitlink]

So the compiler would have done this (and does so if we comment out our unsafe impl):

unsafe impl Send for A<String> {}
// as part of:
unsafe impl Send for A<T> where T: Send {}

But our unsafe impl tells the compiler to disregard its auto trait rules and instead use our "rule" (impl), i.e. we tell the compiler that it is not safe to Send values of type A<T> unless T: Copy?

[Centril]

Yep, pretty much.

[awaitlink]

@Centril I think this is ready for merging now.

[Centril]

Yep; Thanks!