add way to skip the formatting of the argument list of a function only

[gnzlbg]

I want to skip the formatting of the argument list of a function, while allowing rustfmt to format the contents of the function. Using rustfmt_skip on the function currently disables formatting for the whole function.

[juarezr]

What about:

#![rustfmt::skip::option(fn_args_layout)]
fn start_storing_docs(
    writer: usize, dir: PathBuf, name: String, consumer: Receiver<Documents>, progress: Sender<u64>,
) {
    // ...
}

IMHO his could be a more generic mechanism available for all blocks and statements:

    // ...
    #[rustfmt::skip::option(use_small_heuristics)]
    let response = Client::new()
        .post(url)
        .headers(construct_headers())
        .body(content)
        .send()?;
    // ...

Maybe two new generic diretives for #[rustfmt::...]:

1. #[rustfmt::skip::option(option1 , option2, ...)] for disabling one or more formatting options.
2. #[rustfmt::override(option1 = value1 , option2 = value1, ...)] for override the value of the global formatting options.
3. When using the format #[rustfmt::...] they apply only on the block/statement/construct level and they inner child.
4. When using the format #![rustfmt::...] they apply to the whole context like other #[cfg] diretives.
5. These would disable/override the default formatting option from cargo fmt or a custom formatting option specified in the rustfmt.toml file

This way it's possible to fine tune any formatting in any block, statement or language construct.

Any thoughts?