Extension compatibility with Vivaldi Browser

[Roeshimi]

Hi there,
I've recently started using the Vivaldi browser and sadly the Chrome extension does not work correctly.
As you can see, when you type "c" followed by a space, it does not go into the "search mode" (if that's the right term)

[merill]

Sorry, I don't have the bandwidth to support browsers outside the mainstream.

If anyone is willing to submit a PR with a fix, I'm happy to review.