Fix LifetimeParam::lifetime_bounds invalid implement

Lifetime node example:

```
[email protected]
  [email protected]
    [email protected] "'a"
  [email protected] ":"
  [email protected] " "
  [email protected]
    [email protected]
      [email protected]
        [email protected] "'b"
```

Author: A4-Tacks

crates/syntax/src/ast/node_ext.rs

@@ -12,8 +12,8 @@ use rowan::{GreenNodeData, GreenTokenData};
 use crate::{
     NodeOrToken, SmolStr, SyntaxElement, SyntaxToken, T, TokenText,
     ast::{
-        self, AstNode, AstToken, HasAttrs, HasGenericArgs, HasGenericParams, HasName, SyntaxNode,
-        support,
+        self, AstNode, AstToken, HasAttrs, HasGenericArgs, HasGenericParams, HasName,
+        HasTypeBounds, SyntaxNode, support,
     },
     ted,
 };
@@ -912,10 +912,10 @@ impl ast::Visibility {
 
 impl ast::LifetimeParam {
     pub fn lifetime_bounds(&self) -> impl Iterator<Item = SyntaxToken> {
-        self.syntax()
-            .children_with_tokens()
+        self.type_bound_list()
+            .into_iter()
+            .flat_map(|it| it.syntax().descendants_with_tokens())
             .filter_map(|it| it.into_token())
-            .skip_while(|x| x.kind() != T![:])
             .filter(|it| it.kind() == T![lifetime_ident])
     }
 }