Auto merge of #79275 - integer32llc:doc-style, r=jonas-schievink

More consistently use spaces after commas in lists in docs

This PR changes instances of lists that didn't use spaces after commas, like `vec![1,2,3]`, to `vec![1, 2, 3]` to be more consistent with idiomatic Rust style (the way these were looks strange to me, especially because there are often lists that *do* use spaces after the commas later in the same code block 😬).

I noticed one of these in an example in the stdlib docs and went looking for more, but as far as I can see, I'm only changing those spots in user-facing documentation or rustc output, and the changes make no semantic difference.

library/alloc/src/collections/btree/map.rs

@@ -1037,7 +1037,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
     /// let mut count: BTreeMap<&str, usize> = BTreeMap::new();
     ///
     /// // count the number of occurrences of letters in the vec
-    /// for x in vec!["a","b","a","c","a","b"] {
+    /// for x in vec!["a", "b", "a", "c", "a", "b"] {
     ///     *count.entry(x).or_insert(0) += 1;
     /// }
     ///

library/alloc/src/collections/vec_deque/mod.rs

@@ -1962,7 +1962,7 @@ impl<T> VecDeque<T> {
     /// ```
     /// use std::collections::VecDeque;
     ///
-    /// let mut buf: VecDeque<_> = vec![1,2,3].into_iter().collect();
+    /// let mut buf: VecDeque<_> = vec![1, 2, 3].into_iter().collect();
     /// let buf2 = buf.split_off(1);
     /// assert_eq!(buf, [1]);
     /// assert_eq!(buf2, [2, 3]);
@@ -2514,10 +2514,10 @@ impl<T> VecDeque<T> {
     ///          (3, 1), (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
     ///          (1, 21), (2, 34), (4, 55)].into();
     ///
-    /// assert_eq!(deque.binary_search_by_key(&13, |&(a,b)| b),  Ok(9));
-    /// assert_eq!(deque.binary_search_by_key(&4, |&(a,b)| b),   Err(7));
-    /// assert_eq!(deque.binary_search_by_key(&100, |&(a,b)| b), Err(13));
-    /// let r = deque.binary_search_by_key(&1, |&(a,b)| b);
+    /// assert_eq!(deque.binary_search_by_key(&13, |&(a, b)| b),  Ok(9));
+    /// assert_eq!(deque.binary_search_by_key(&4, |&(a, b)| b),   Err(7));
+    /// assert_eq!(deque.binary_search_by_key(&100, |&(a, b)| b), Err(13));
+    /// let r = deque.binary_search_by_key(&1, |&(a, b)| b);
     /// assert!(matches!(r, Ok(1..=4)));
     /// ```
     #[unstable(feature = "vecdeque_binary_search", issue = "78021")]

library/alloc/src/vec.rs

@@ -1041,7 +1041,7 @@ impl<T, A: AllocRef> Vec<T, A> {
     ///     }
     ///     x.set_len(size);
     /// }
-    /// assert_eq!(&*x, &[0,1,2,3]);
+    /// assert_eq!(&*x, &[0, 1, 2, 3]);
     /// ```
     #[stable(feature = "vec_as_ptr", since = "1.37.0")]
     #[inline]
@@ -1594,7 +1594,7 @@ impl<T, A: AllocRef> Vec<T, A> {
     /// # Examples
     ///
     /// ```
-    /// let mut vec = vec![1,2,3];
+    /// let mut vec = vec![1, 2, 3];
     /// let vec2 = vec.split_off(1);
     /// assert_eq!(vec, [1]);
     /// assert_eq!(vec2, [2, 3]);