Updates compiler error E0046 with new format
Addresses #35209 as part of #35233.
r? @jonathandturner
I've repeated the following in my code. If this is something not desirable then let me know if there's any process to make this any cleaner. Thank you.
```rust
missing_items.iter()
.map(|name| name.to_string())
.collect::<Vec<_>>().join("`, `"))
```
