Feature Request: new function html_attr to output html attributes the easy way

[axten]

Hi, I would suggest to add a new helper function to manage html attributes in a simple way.

twig example:

    {% set attr = {
        'aria-expandend': 'false',
        disabled: true,
        hidden: false,
        id: 123,
        title: 'cli"<ck',
    } %}

    <button{{ html_attr(attr) }}>Test</button>

output:

<button aria-expandend="false" disabled id="123" title="cli&quot;&lt;ck">Test</button>

PR: #3199

[fabpot]

Closing as there is a PR; let's discuss there.