When encountering a call corresponding to an item marked as unstable behind a feature flag, provide a structured suggestion pointing at where in the crate the `#![feature(..)]` needs to be written.
```
error: `foobar` is not yet stable as a const fn
--> $DIR/const-stability-attribute-implies-no-feature.rs:12:5
|
LL | foobar();
| ^^^^^^^^
|
help: add `#![feature(const_foobar)]` to the crate attributes to enable
|
LL + #![feature(const_foobar)]
|
```
Fix#81370.
a47fee50bd