Update prettier, change print width to 120, and enable dangling commas for functions

[julienw]

Fixes #370

I didn't regenerate all workloads (yet). Please do not land this just yet, this PR is here so that we can decide about #370.

I made separate commits so that we can easily see the effect of each action:

1. update Prettier
2. add dangling commas to functions
3. change printWidth to 120

[rniwa]

At this point, I'd rather not take a huge PR like this into the repo right before the release even if it should not have any real impact on performance in theory.

[rniwa]

Adding v3.1 label to match the label on https://github.com/WebKit/Speedometer/issues/370

[julienw]

At this point, I'd rather not take a huge PR like this into the repo right before the release even if it should not have any real impact on performance in theory.

fully agreed, this was definitely meant for after the release. Thanks for adding the label.

[julienw]

Loooking good. I guess we can redo the formatting now that we've released?

yeah, I was waiting to see if there was some interest before doing more work :-)

[camillobruni]

I'd definitely prefer some width-limit, especially for the html files.

[julienw]

I rebased and refreshed all affected benchmarks.

On my Linux:

Firefox Before:

Firefox After:

Chrome Before:

Chrome After:

(I don't have a Mac so I can't try Safari)