[rustdoc] invalid trait doc generation

[GuillaumeGomez]

When rustdoc generates doc from trait implementation, it could replace generic ones with the one we have. Example with http://doc.rust-lang.org/nightly/std/cell/struct.RefCell.html :

fn eq(&self, other: &RefCell<T>) -> bool;

This method tests for self and other values to be equal, and is used by ==. Read more

fn ne(&self, other: &Rhs) -> bool;

This method tests for !=.

eq()'s other argument is &RefCell, but that's not the case for ne(). It should be fixed.

cc @nox

[GuillaumeGomez]

I'm working on it.

[alexcrichton]

I believe this is a dupe of #14072, so I'm going to close this in favor of that.