Config file parsing breaks on multi-line arrays with no element on the first line

[beta382]

Using the v2.5.0 mono-header from releases.

main.cpp:

#include <vector>

#include "CLI11.hpp"

int main(int argc, char** argv) {
    CLI::App app;
    argv = app.ensure_utf8(argv);

    std::vector<int> test;
    app.add_option("--test", test);
    
    app.set_config("--config");

    CLI11_PARSE(app, argc, argv);
    return 0;
}

config.toml

test = [
1,2,3]

Run as:

$ g++ main.cpp 
$ ./a.out --config config.toml
Could not convert: --test = [
Run with --help for more information.
$

---

I encountered this importing a TOML generated by Toml++, which unconditionally wraps long arrays as:

array = [
    'item1',
    'item2',
    'item3',
    'item4'
]

(indent optional)

Given that this is valid TOML, CLI11 should be able to parse it.

#528 originally implemented multi-line array support, but missed this case

[phlptp]

I will look into it