fix: fix some assist indent

[A4-Tacks]

For exprs like non_newline.call(newline) non_newline(newline) etc, is it worth adding some if in #21719 to exclude newline?

Example

Before this PR:

fn main() {
    {
        {
            loop {
                if let Some(_) = foo(
                            "xxx"
                        )
            {
                    bar(
                        "xxx",
                    );
                } else {
                    break;
                }
            }
        }
    }
}

After this PR:

fn main() {
    {
        {
            loop {
                if let Some(_) = foo(
                    "xxx"
                )
                {
                    bar(
                        "xxx",
                    );
                } else {
                    break;
                }
            }
        }
    }
}

[ChayimFriedman2]

@A4-Tacks, I already said many times I think we should not explicitly fixing whitespaces in assists. You seem to disagree. Therefore, I would like to set a policy wrt. this:

@rust-lang/rust-analyzer, do you think we should accept code changes that fix whitespaces in assists?