Regressed UI in tests/ui/endpoint/dynamic_schema_wrong_type.rs

[msrd0]

Updating the Rust compiler used for trybuild to 1.78 added this weird suggestion to wrap a string in a closure:

error[E0631]: type mismatch in function arguments
  --> tests/ui/endpoint/dynamic_schema_wrong_type.rs:16:21
   |
8  | fn schema(_: u16) -> String {
   | --------------------------- found signature defined here
...
16 | #[read_all(schema = "schema", status_codes = "status_codes")]
   |                     ^^^^^^^^ expected due to this
   |
   = note: expected function signature `fn(StatusCode) -> _`
              found function signature `fn(u16) -> _`
   = note: required for `fn(u16) -> std::string::String {schema}` to implement `CustomSchema`
help: consider wrapping the function in a closure
   |
16 | #[read_all(schema = |arg0: StatusCode| "schema"(/* u16 */), status_codes = "status_codes")]
   |                     ++++++++++++++++++         +++++++++++

error[E0271]: expected `status_codes` to be a fn item that returns `Vec<StatusCode>`, but it returns `Vec<u16>`
  --> tests/ui/endpoint/dynamic_schema_wrong_type.rs:16:46
   |
16 | #[read_all(schema = "schema", status_codes = "status_codes")]
   |                                              ^^^^^^^^^^^^^^ expected `Vec<StatusCode>`, found `Vec<u16>`
   |
   = note: expected struct `Vec<StatusCode>`
              found struct `Vec<u16>`
   = note: required for `fn() -> Vec<u16> {status_codes}` to implement `CustomStatusCodes`