Rollup merge of rust-lang#83270 - steffahn:missing_word_in_skip_while…

…_doc, r=joshtriplett

Fix typo/inaccuracy in the documentation of Iterator::skip_while

One of the examples used to say “this leads to a possibly confusing situation, where the type of the closure is a double reference” while _actually_ referring to the type of the closure _argument_.

This PR just changes a single word in documentation.

````@rustbot```` modify labels: A-iterators, T-doc, T-lang

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

@@ -1012,7 +1012,7 @@ pub trait Iterator {
     ///
     /// Because the closure passed to `skip_while()` takes a reference, and many
     /// iterators iterate over references, this leads to a possibly confusing
-    /// situation, where the type of the closure is a double reference:
+    /// situation, where the type of the closure argument is a double reference:
     ///
     /// ```
     /// let a = [-1, 0, 1];