Rollup merge of #85888 - steffahn:fix_internal_trustedrandomaccess_docs, r=Mark-Simulacrum

Fix typo in internal documentation for `TrustedRandomAccess`

`next_back` is a method of DoubleEndedIterator, not Iterator.

library/core/src/iter/adapters/zip.rs

@@ -434,7 +434,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 ///    called on `self`:
 ///     * `std::clone::Clone::clone()`
 ///     * `std::iter::Iterator::size_hint()`
-///     * `std::iter::Iterator::next_back()`
+///     * `std::iter::DoubleEndedIterator::next_back()`
 ///     * `std::iter::Iterator::__iterator_get_unchecked()`
 ///     * `std::iter::TrustedRandomAccess::size()`
 ///