Remove doc using cargo xtask codegen.

docs/user/assists.md

@@ -259,30 +259,6 @@ fn main() {
 }
 ```
 
-## `change_lifetime_anon_to_named`
-
-Change an anonymous lifetime to a named lifetime.
-
-```rust
-// BEFORE
-impl Cursor<'_<|>> {
-    fn node(self) -> &SyntaxNode {
-        match self {
-            Cursor::Replace(node) | Cursor::Before(node) => node,
-        }
-    }
-}
-
-// AFTER
-impl<'a> Cursor<'a> {
-    fn node(self) -> &SyntaxNode {
-        match self {
-            Cursor::Replace(node) | Cursor::Before(node) => node,
-        }
-    }
-}
-```
-
 ## `change_return_type_to_result`
 
 Change the function's return type to Result.