Please consider restoring manual lens correction functionality from Classic to the new Lightroom. I would like to be able to flexibly correct vignetting in images for which Adobe lens profiles are unavailable without round-tripping to Photoshop.Thank you!
In the meantime, you can brighten the edges with a radial gradient. Save a preset with just this so that you can apply it quickly to additional images. Alternatively, if you're not going to crop an image, you can use post-crop vignetting in the Effects panel.