Leave wrapped struct/function as is even not touch the max_width

[clouds56]

With vscode extension rust-analyzer, the (visual) line width in editor might not the same as the width in text file.
e.g.

fn f(very_very_very_very_long_arg_1: i32, very_very_very_very_long_arg_2: i32) {}

fn main() {
  f("1".parse().expect("true"), "2".parse().expect("true")); // what rustfmt see
}

with rust-analyzer it would be rendered as

fn main() {
  f(very_very_very_very_long_arg_1: "1".parse().expect("true"), very_very...: "2".parse().expect("true")); // what we see
}

which is much longer.
The question here is not that rustfmt would not turn this f("1".parse().expect("true"), "2".parse().expect("true")); into vertical format, it is about rustfmt would shrink my vertical formatting version into oneline.

// I write it vertically, after `cargo fmt` it would be forced be into one line
fn main() {
  f(
    "1".parse().expect("true"),
    "2".parse().expect("true"),
  );
}

I think we should add an option like no_force_same_line that rustfmt would only break long line but not combine lines, so that when I explicitly write vertical formatting code, rustfmt would leave it as is.