feat(lsp): goto definition of trait

[kobyhallx]

Considering snippet

trait Fieldable {
    fn to_field(self) -> Field;
}

impl Fieldable for u32 {
    fn to_field(self) -> Field {
        let res = self as Field;
        res * 3    
    }
}

fn main(x: u32) {
    assert(x.to_field() == 15);
}

User should be able to navigate to definition of Fieldable when on that symbol of line impl Fieldable for u32 { which should result in navigation to Fieldable symbol of trait Fieldable {.