Rollup merge of rust-lang#104643 - pnkfelix:examples-for-chunks-remainder, r=scottmcm

add examples to chunks remainder methods.

add examples to chunks remainder methods.

my motivation for adding the examples was to make it very clear that the state of the iterator (in terms of where its cursor lies) has no effect on what remainder returns.

Also fixed some links to rchunk remainder methods.

Author: matthiaskrgr

library/core/src/slice/iter.rs

@@ -1834,6 +1834,20 @@ impl<'a, T> ChunksExact<'a, T> {
     /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// let slice = ['l', 'o', 'r', 'e', 'm'];
+    /// let mut iter = slice.chunks_exact(2);
+    /// assert_eq!(iter.remainder(), &['m'][..]);
+    /// assert_eq!(iter.next(), Some(&['l', 'o'][..]));
+    /// assert_eq!(iter.remainder(), &['m'][..]);
+    /// assert_eq!(iter.next(), Some(&['r', 'e'][..]));
+    /// assert_eq!(iter.remainder(), &['m'][..]);
+    /// assert_eq!(iter.next(), None);
+    /// assert_eq!(iter.remainder(), &['m'][..]);
+    /// ```
     #[must_use]
     #[stable(feature = "chunks_exact", since = "1.31.0")]
     pub fn remainder(&self) -> &'a [T] {
@@ -2869,7 +2883,7 @@ unsafe impl<T> Sync for RChunksMut<'_, T> where T: Sync {}
 /// ```
 ///
 /// [`rchunks_exact`]: slice::rchunks_exact
-/// [`remainder`]: ChunksExact::remainder
+/// [`remainder`]: RChunksExact::remainder
 /// [slices]: slice
 #[derive(Debug)]
 #[stable(feature = "rchunks", since = "1.31.0")]
@@ -2892,6 +2906,20 @@ impl<'a, T> RChunksExact<'a, T> {
     /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// let slice = ['l', 'o', 'r', 'e', 'm'];
+    /// let mut iter = slice.rchunks_exact(2);
+    /// assert_eq!(iter.remainder(), &['l'][..]);
+    /// assert_eq!(iter.next(), Some(&['e', 'm'][..]));
+    /// assert_eq!(iter.remainder(), &['l'][..]);
+    /// assert_eq!(iter.next(), Some(&['o', 'r'][..]));
+    /// assert_eq!(iter.remainder(), &['l'][..]);
+    /// assert_eq!(iter.next(), None);
+    /// assert_eq!(iter.remainder(), &['l'][..]);
+    /// ```
     #[must_use]
     #[stable(feature = "rchunks", since = "1.31.0")]
     pub fn remainder(&self) -> &'a [T] {
@@ -3031,7 +3059,7 @@ unsafe impl<'a, T> TrustedRandomAccessNoCoerce for RChunksExact<'a, T> {
 /// ```
 ///
 /// [`rchunks_exact_mut`]: slice::rchunks_exact_mut
-/// [`into_remainder`]: ChunksExactMut::into_remainder
+/// [`into_remainder`]: RChunksExactMut::into_remainder
 /// [slices]: slice
 #[derive(Debug)]
 #[stable(feature = "rchunks", since = "1.31.0")]