Non-exhaustive pattern match warning with guards

In [this stackoverflow question](https://stackoverflow.com/questions/69197294) the asker presents this code:

```haskell
data Tree = Leaf | Node Int Tree Tree
deriving (Eq, Show, Read, Ord)

insert :: Int -> Tree -> Tree
insert n Leaf = Node n Leaf Leaf
insert n tree@(Node num lt rt)
| n < num = Node num (insert n lt) rt
| n > num = Node num lt (insert n rt)
| n == num = tree
```

Which produces the following warning (with `-Wall`):

```
Test.hs:5:1: warning: [-Wincomplete-patterns]
Pattern match(es) are non-exhaustive
In an equation for ‘insert’:
Patterns not matched:
_ (Node _ Leaf Leaf)
_ (Node _ Leaf (Node _ _ _))
_ (Node _ (Node _ _ _) Leaf)
_ (Node _ (Node _ _ _) (Node _ _ _))
|
5 | insert n Leaf = Node n Leaf Leaf
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...
```

The list of "patterns not matched" here is strange, it seems to me that the pattern not matched is just `_ (Node _ _ _)` and I think it should also mention something about the guards.