Don't ICE while suggesting updating item path.
When an item isn't found, we may suggest an appropriate import to `use`. Along with that, we also suggest updating the path to work with the `use`. Unfortunately, if the code in question originates from a macro, the span used to indicate which part of the path needs updating may not be suitable and cause an ICE (*). Since, such code is not adjustable directly by the user without modifying the macro, just skip the suggestion in such cases.
(*) The ICE happens because the emitter want to indicate to the user what code to delete by referencing a certain span. But in this case, said span has `lo == hi == 0` which means it thinks it's a dummy span. Adding a space before the proc macro attribute is enough to stop it from ICE'ing but even then the suggestion doesn't really make any sense:
```
help: if you import `DataStore`, refer to it directly
|
1 - #[dbstruct::dbstruct]
1 + #[dbstruct::dbstruct]
```
Since suggestions are best-effort, I just gated this one on `can_be_used_for_suggestions` which catches cases like this.
Fixes#100199
fac84e8bb6