Documentation for `fetch_update` talks about success and failure orderings, but the arguments are for fetch and store orderings

[nagisa]

They may be the same but when you read

pub fn fetch_update<F>(&self, set_order: Ordering, fetch_order: Ordering, f: F) -> Result<usize, usize> where F: FnMut(usize) -> Option<usize>, 

(note set/fetch_order), the two paragraphs that talk about the operation ordering don't make all that much sense. We should either rename the arguments accordingly or adjust the documentation to talk about set and fetch orderings instead.