finished proposals: reverse table order

[zhangenming]

at page https://github.com/tc39/proposals/blob/main/finished-proposals.md

run

[...$$('.react-code-lines')[0].childNodes]
.map(e=>e.innerText)
.filter(e=>e.startsWith('| ')) // startsWith('| [') // no, this has bug for `Class Fields` item line
.reverse()
.slice(0,-2) // dirty data
.join('\n')

get reversed table

and i check, use re-reverse data with origin data

Fixes #539

[ljharb]

looks good, thanks!