190a1a7f74
suggest declaring modules when file found but module not defined
suggests declaring modules when a module is found but not defined, i.e
```
├── main.rs: `use thing::thang;`
└── thing.rs: `struct thang`
```
or
```
├── main.rs: `use thing::thang;`
└── thing
└── mod.rs: `struct thang`
```
which currently is just
```rust
error[E0432]: unresolved import `yeah`
--> src/main.rs:1:1
|
1 | use thing::thang;
| ^^^^^ use of unresolved module or unlinked crate `thing`
|
```
but now would have this nice help:
```text
= help: you may have forgotten to declare the module `thing`. use `mod thing` in this file to declare this module.
```
|
||
|---|---|---|
| .. | ||
| src | ||
| Cargo.toml | ||
| messages.ftl | ||