Symfony version(s) affected: symfony/yaml:3.4.35, symfony/yaml:5.1.8
The issue affects the latest version at time of writing.

Description
YAML fails to parse perfectly valid JSON, even though YAML is a superset of JSON:

[
  ["entry1", {}],
  ["entry2", {"entry3": "entryvalue"}]
]

The YAML/JSON passes when ran on http://www.yamllint.com and https://yaml-online-parser.appspot.com.

How to reproduce

// composer.json
{
    "name": "demo/yaml-bug",
    "require": {
        "symfony/yaml": "^5.1"
    }
}

<?php
require_once 'vendor/autoload.php';
use Symfony\Component\Yaml\Parser;

$yaml = new Parser();
$yaml_content = <<<YAML
[
  ["entry1", {}],
  ["entry2", {"entry3": "entryvalue"}]
]
YAML;
$yaml->parse($yaml_content);

throws the following:

PHP Fatal error:  Uncaught Symfony\Component\Yaml\Exception\ParseException:
  Malformed inline YAML string: "[["entry1", {}]," at line 2 (near "  ["entry1", {}],").

Possible Solution
To avoid issues like this continuously happening, I believe the library should be capable of parsing every single YAML in the https://github.com/yaml/yaml-test-suite repo.
Or at the bare minimum other valid JSON.

e.g. the first test file I picked up from that repository isn't currently parseable either.