[docs] Iterator fuction `ne` description should use "not equal"

[1oglop1]

Hi, I'm currently learning Rust and English is not my first language on top of which I suffer from dyslexia.
The language style in docs is a bit difficult for me to understand sometimes.

For example docs for the not equal function feels a bit misleading by using the synonym unequal instead of not equal while even the name of the function is the abbreviation of the words Not Equal.

rust/library/core/src/iter/traits/iterator.rs

Line 3724 in 992d154

/// Determines if the elements of this [`Iterator`] are unequal to those of

I'd prefer if docs reflected it and said

/// Determines if the elements of this [`Iterator`] are not equal to those of 

@rustbot claim