Makes Pell work in Microsoft Edge Classic

[antony]

I realise this project is largely dormant but I figure it's useful for people who still use pell, since it is still the smallest, lightest rich editor available.

Using object rest destructuring requires pell to be pushed through babel for transpilation to older JS.

Switching to Object.assign means that it will work in Edge Classic without transpilation.

I don't use Babel on my sites any more because I stopped supporting IE11, so it's important that all libraries can run on Edge Classic without transpilation.

[ghost]

Pell is absolutely great to be maintained a little, thanks @antony for the addition.