feat: support flattened items and comma seperated arguments

[faervan]

use std::collections::HashMap;

use serde::Serialize;
use toml_example::TomlExample;

fn main() {
    let example = ConfigWrapper::toml_example();
    println!("{example}");
}

#[derive(TomlExample, Serialize, PartialEq)]
struct ConfigWrapper {
    #[serde(flatten, default)]
    #[toml_example(nesting)]
    config: Config,

    #[serde(flatten)]
    #[toml_example(nesting, default = hello)]
    map: HashMap<String, NestedNum>,

    #[toml_example(default = ["hello", "{nice :)\""], require)]
    list: Option<Vec<String>>,

    #[toml_example(default = (9999, "super (fancy\\! :-) )"), require)]
    tuple: Option<(usize, String)>,
}

#[derive(TomlExample, Serialize, Default, PartialEq)]
struct Config {
    #[toml_example(default = "abc, de")]
    number: String,
}

#[derive(TomlExample, Serialize, Default, PartialEq)]
struct NestedNum {
    value: usize,
}

The output:

list = ["hello", "{nice :)\""]

tuple = (9999, "super (fancy\\! :-) )")

number = "abc, de"

[hello]
value = 0

Notice the extra line between tuple and number: Should this be or would removing this be the better choice?

close #48

To-do:

• Add tests
• Update crate docs
• Update README

[faervan]

@yanganto This PR should be ready for review now

Or it should not, just detected a non-working case that needs fixing tomorrow

[faervan]

Or rather, recursive nesting does not work regardless of the flattening which I added, so that should be a separate issue probably

[yanganto]

Looks good. Thank you. ❤️

[yanganto]

Or rather, recursive nesting does not work regardless of the flattening which I added, so that should be a separate issue probably

Yeh, I think deep nesting and flatten are not the feature people using at the same time now. We can keep this in a separate issue.