Reword error when data-less enum variant called as function

Given a file like:

```rust
enum Test {
    Variant,
    Variant2 {a: u32},
}

fn main(){
    let x = Test::Variant("Hello");
    let y = Test::Variant2("World");
}
```

The errors now look this way:

```bash
error[E0423]: `Test::Variant2` is the name of a struct or struct variant, but this expression uses it like a function name
  --> file3.rs:10:13
   |
10 |     let y = Test::Variant2("Hello");
   |             ^^^^^^^^^^^^^^ struct called like a function
   |
   = help: did you mean to write: `Test::Variant2 { /* fields */ }`?

error: `Test::Variant` is being called, but it is not a function
 --> file3.rs:9:13
  |
9 |     let x = Test::Variant("World");
  |             ^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: did you mean to write: `Test::Variant`?
note: defined here
 --> file3.rs:2:5
  |
2 |     Variant,
  |     ^^^^^^^

error: aborting due to previous error
```

0 files changed, 0 insertions, 0 deletions