message: update compile-fail test .stderr message
diff: @@ -2,7 +2,7 @@ error[E0599]: no method named `set_id_one` found for struct `MyInput` in the cur
  --> tests/compile-fail/input_struct_id_fields_no_setters.rs:30:11
  |
  7 | #[salsa::input(jar = Jar)]
  - | -------------------------- method `set_id_one` not found for this
  + | -------------------------- method `set_id_one` not found for this struct
  ...
  30 | input.set_id_one(1);
  | ^^^^^^^^^^ help: there is an associated function with a similar name: `id_one`
  