Delay `this post was closed` message for 10-20 seconds

[wooorm]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)

Affected packages and versions: TODO

Steps to reproduce

syntax-tree/hast-util-from-dom#13 (comment)

Expected behavior

Delay

Actual behavior

No delay