Unrolled build for #152818

Rollup merge of #152818 - mgeier:doc-by_ref-link, r=scottmcm

DOC: do not link to "nightly" in Iterator::by_ref() docstring

I happened to see that the link in the docstring https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.by_ref points to the "nightly" docs instead of "stable".

I'm not sure if my fix actually works because I didn't get `cargo doc` to run on my local computer.

Author: rust-timer

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

@@ -1908,7 +1908,7 @@ pub const trait Iterator {
     /// without giving up ownership of the original iterator,
     /// so you can use the original iterator afterwards.
     ///
-    /// Uses [`impl<I: Iterator + ?Sized> Iterator for &mut I { type Item = I::Item; ...}`](https://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#impl-Iterator-for-%26mut+I).
+    /// Uses [`impl<I: Iterator + ?Sized> Iterator for &mut I { type Item = I::Item; ...}`](Iterator#impl-Iterator-for-%26mut+I).
     ///
     /// # Examples
     ///