Indent a note to make folding work nicer

Co-authored-by: Joshua Nelson <joshua@yottadb.com>

library/core/src/slice/mod.rs

@@ -3358,8 +3358,9 @@ mod private_slice_index {
     on(T = "str", label = "string indices are ranges of `usize`",),
     on(
         all(any(T = "str", T = "&str", T = "std::string::String"), _Self = "{integer}"),
-        note = "you can use `.chars().nth()` or `.bytes().nth()`
-see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+        note = "you can use `.chars().nth()` or `.bytes().nth()`\n\
+                for more information, see chapter 8 in The Book: \
+                <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
     ),
     message = "the type `{T}` cannot be indexed by `{Self}`",
     label = "slice indices are of type `usize` or ranges of `usize`"

src/test/ui/str/str-idx.stderr

@@ -6,7 +6,7 @@ LL |     let _: u8 = s[4];
    |
    = help: the trait `SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
-           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+           for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
    = note: required because of the requirements on the impl of `Index<{integer}>` for `str`
 
 error[E0277]: the type `str` cannot be indexed by `{integer}`
@@ -17,7 +17,7 @@ LL |     let _ = s.get(4);
    |
    = help: the trait `SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
-           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+           for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
 
 error[E0277]: the type `str` cannot be indexed by `{integer}`
   --> $DIR/str-idx.rs:5:29
@@ -27,7 +27,7 @@ LL |     let _ = s.get_unchecked(4);
    |
    = help: the trait `SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
-           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+           for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
 
 error[E0277]: the type `str` cannot be indexed by `char`
   --> $DIR/str-idx.rs:6:17

src/test/ui/str/str-mut-idx.stderr

@@ -39,7 +39,7 @@ LL |     s.get_mut(1);
    |
    = help: the trait `SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
-           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+           for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
 
 error[E0277]: the type `str` cannot be indexed by `{integer}`
   --> $DIR/str-mut-idx.rs:11:25
@@ -49,7 +49,7 @@ LL |     s.get_unchecked_mut(1);
    |
    = help: the trait `SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
-           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+           for more information, see chapter 8 in The Book: <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
 
 error[E0277]: the type `str` cannot be indexed by `char`
   --> $DIR/str-mut-idx.rs:13:5