fix: make bool_to_enum assist create enum at top-level
This pr makes the `bool_to_enum` assist create the `enum` at the next closest module block or at top-level, which fixes a few tricky cases such as with an associated `const` in a trait or module:
```rust
trait Foo {
const $0BOOL: bool;
}
impl Foo for usize {
const BOOL: bool = true;
}
fn main() {
if <usize as Foo>::BOOL {
println!("foo");
}
}
```
Which now properly produces:
```rust
#[derive(PartialEq, Eq)]
enum Bool { True, False }
trait Foo {
const BOOL: Bool;
}
impl Foo for usize {
const BOOL: Bool = Bool::True;
}
fn main() {
if <usize as Foo>::BOOL == Bool::True {
println!("foo");
}
}
```
I also think it's a bit nicer, especially for local variables, but didn't really know to do it in the first PR :)