Cleanup code suggestion for into_iter_without_iter

Reorder the suggested code for the `IntoIterator` to match the ordering of the trait declaration:

```rust
impl IntoIterator for ... {
    type Item = ...;
    type IntoIter = ...;
```

Author: nyurik

clippy_lints/src/iter_without_into_iter.rs

@@ -247,8 +247,8 @@ impl {self_ty_without_ref} {{
                     let sugg = format!(
                         "
 impl IntoIterator for {self_ty_snippet} {{
-    type IntoIter = {ret_ty};
     type Item = {iter_ty};
+    type IntoIter = {ret_ty};
     fn into_iter(self) -> Self::IntoIter {{
         self.iter()
     }}

tests/ui/iter_without_into_iter.stderr

@@ -13,8 +13,8 @@ help: consider implementing `IntoIterator` for `&S1`
    |
 LL + 
 LL + impl IntoIterator for &S1 {
-LL +     type IntoIter = std::slice::Iter<'_, u8>;
 LL +     type Item = &u8;
+LL +     type IntoIter = std::slice::Iter<'_, u8>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -34,8 +34,8 @@ help: consider implementing `IntoIterator` for `&mut S1`
    |
 LL + 
 LL + impl IntoIterator for &mut S1 {
-LL +     type IntoIter = std::slice::IterMut<'_, u8>;
 LL +     type Item = &mut u8;
+LL +     type IntoIter = std::slice::IterMut<'_, u8>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -55,8 +55,8 @@ help: consider implementing `IntoIterator` for `&S3<'a>`
    |
 LL + 
 LL + impl IntoIterator for &S3<'a> {
-LL +     type IntoIter = std::slice::Iter<'_, u8>;
 LL +     type Item = &u8;
+LL +     type IntoIter = std::slice::Iter<'_, u8>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -76,8 +76,8 @@ help: consider implementing `IntoIterator` for `&mut S3<'a>`
    |
 LL + 
 LL + impl IntoIterator for &mut S3<'a> {
-LL +     type IntoIter = std::slice::IterMut<'_, u8>;
 LL +     type Item = &mut u8;
+LL +     type IntoIter = std::slice::IterMut<'_, u8>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -96,8 +96,8 @@ help: consider implementing `IntoIterator` for `&S8<T>`
    |
 LL + 
 LL + impl IntoIterator for &S8<T> {
-LL +     type IntoIter = std::slice::Iter<'static, T>;
 LL +     type Item = &T;
+LL +     type IntoIter = std::slice::Iter<'static, T>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -117,8 +117,8 @@ help: consider implementing `IntoIterator` for `&S9<T>`
    |
 LL + 
 LL + impl IntoIterator for &S9<T> {
-LL +     type IntoIter = std::slice::Iter<'_, T>;
 LL +     type Item = &T;
+LL +     type IntoIter = std::slice::Iter<'_, T>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -138,8 +138,8 @@ help: consider implementing `IntoIterator` for `&mut S9<T>`
    |
 LL + 
 LL + impl IntoIterator for &mut S9<T> {
-LL +     type IntoIter = std::slice::IterMut<'_, T>;
 LL +     type Item = &mut T;
+LL +     type IntoIter = std::slice::IterMut<'_, T>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }
@@ -162,8 +162,8 @@ help: consider implementing `IntoIterator` for `&Issue12037`
    |
 LL ~         
 LL + impl IntoIterator for &Issue12037 {
-LL +     type IntoIter = std::slice::Iter<'_, u8>;
 LL +     type Item = &u8;
+LL +     type IntoIter = std::slice::Iter<'_, u8>;
 LL +     fn into_iter(self) -> Self::IntoIter {
 LL +         self.iter()
 LL +     }