Rollup merge of #140196 - Kivooeo:new-fix-two, r=wesleywiser

Improved diagnostics for non-primitive cast on non-primitive types (`Arc`, `Option`)

here is a small fix that improving error messaging when user is trying to do something like this
```rust
let _ = "x" as Arc<str>;
let _ = 2 as Option<i32>;
```

before it looks like this
```rust
error[E0605]: non-primitive cast: `&'static str` as `Arc<str>`
 --> src\main.rs:3:13
  |
3 |     let _ = "x" as Arc<str>;
  |             ^^^^^^^^^^^^^^^ help: consider using the `From` trait instead: `Arc<str>::from("x")`

error[E0605]: non-primitive cast: `i32` as `Option<i32>`
 --> src\main.rs:4:13
  |
4 |     let _ = 2 as Option<i32>;
```
which looks horrible to be honest
so i made a small fix that make errors looks like this
```rust
error[E0605]: non-primitive cast: `&'static str` as `Arc<str>`
  |
3 |     let _ = "x" as Arc<str>;
  |             ^^^^^^^^^^^^^^^
  |
  = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
help: consider using the `From` trait instead
  |
3 -     let _ = "x" as Arc<str>;
3 +     let _ = Arc::<str>::from("x");
  |

error[E0605]: non-primitive cast: `i32` as `Option<i32>`
  |
4 |     let _ = 2 as Option<i32>;
  |             ^^^^^^^^^^^^^^^^
  |
  = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
help: consider using the `From` trait instead
  |
4 -     let _ = 2 as Option<i32>;
4 +     let _ = Option::<i32>::from(2);
```

**What improves?**
1) `Arc<str>::from("x")` which makes no sense because of missing `::`
2) readability

**Related Issue**
fixes #135412

Author: matthiaskrgr