Erroneous suggestion to add .field when matching arrays

[compiler-errors]

Given this code:

struct S(());

fn main() {
    let array = [S(())];
    
    match array {
        [()] => {}
        _ => {}
    }
}

The current output is:

error[E0308]: mismatched types
 --> src/main.rs:7:10
  |
6 |     match array {
  |           ----- this expression has type `[S; 1]`
7 |         [()] => {}
  |          ^^ expected struct `S`, found `()`
  |
help: you might have meant to use field `0` whose type is `()`
  |
6 |     match array.0 {
  |           ~~~~~~~

For more information about this error, try `rustc --explain E0308`.
error: could not compile `playground` due to previous error

We should suppress the help: suggestion in this case, since it's not possible to apply that change.

[compiler-errors]

The bug probably exists in suggest_accessing_field_where_appropriate in rustc_infer::infer::error_reporting. I've been touching stuff around that file, so I can claim this issue and put up a fix!

cc: @estebank since I mentioned this error in #91022

@rustbot claim