Rollup merge of #130845 - RalfJung:utf8chunk, r=tgross35

Utf8Chunks: add link to Utf8Chunk

It is currently surprisingly non-trivial to go from the `utf8_chunks` method to the docs of the `valid`/`invalid` methods used in the example. This should help.

library/core/src/str/lossy.rs

@@ -8,6 +8,8 @@ impl [u8] {
     /// Creates an iterator over the contiguous valid UTF-8 ranges of this
     /// slice, and the non-UTF-8 fragments in between.
     ///
+    /// See the [`Utf8Chunk`] type for documenation of the items yielded by this iterator.
+    ///
     /// # Examples
     ///
     /// This function formats arbitrary but mostly-UTF-8 bytes into Rust source
@@ -148,6 +150,8 @@ fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
 /// If you want a simple conversion from UTF-8 byte slices to string slices,
 /// [`from_utf8`] is easier to use.
 ///
+/// See the [`Utf8Chunk`] type for documenation of the items yielded by this iterator.
+///
 /// [byteslice]: slice
 /// [`from_utf8`]: super::from_utf8
 ///