Fix sway formatting turns op + = into op + + = which breaks the build command because it is not a valid expression

[kayagokalp]

closes #1945

Until we are ready to switch to formatter v2, I am pushing a quick fix as this seems fairly easy to fix and the bug is breaking the build process.

[Braqzen]

Shouldn't this have a test case?

[kayagokalp]

I wasn't sure whether we should have a test or not since:

• Handling of = sign part does not have one too
• We are going to be removing the v1 formatter soon (wasn't sure if we should add more noise)

But I think we can add one so that we are sure it does not touch += as it used to do (if you also think that would be a better approach to follow)

Does something like this seem good?:

    #[test]
    fn test_plus_equal() {
        let correct_sway_code = r#"script;
fn main() {
    let mut a = 1;
    a += 1;
}
"#;
        let sway_code = r#"script;
fn main() {
    let mut a = 1;
    a += 1;
}
"#;
        let result = get_formatted_data(sway_code.into(), OPTIONS, None);
        assert!(result.is_ok());
        let (_, formatted_code) = result.unwrap();
        assert_eq!(correct_sway_code, formatted_code);
    }

[mohammadfawaz]

Shouldn't we also do the same for other operators: -=, *=, etc.? I suspect hey suffer from the same problem.

A list of possible operators is here: #1783

[kayagokalp]

Yes, that seems correct, I can see that this happens with:

• -=
• *=
• /=

but <<= and >>= seem to be formatted correctly.