expand all files in PR files view

expand_all_PR.js

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}
async function expand_all() {
    while (true) {
        if ($$('tr.js-expandable-line a').map(function(x){x.click()}).length > 0) {
            await sleep(200);
        } else { break; }
    }
}
expand_all();