Add alias from k6-experimental/browser to k6-browser

[heitortsergent]

What?

This adds a redirect from https://grafana.com/docs/k6/latest/javascript-api/k6-experimental/browser/ to https://grafana.com/docs/k6/latest/javascript-api/k6-browser/. The broken link was reported by @tom-miseur. 🙇

Checklist

• I have used a meaningful title for the PR.
• I have described the changes I've made in the "What?" section above.
• I have performed a self-review of my changes.
• I have run the npm start command locally and verified that the changes look good.

• I have made my changes in the docs/sources/next folder of the documentation.
• I have reflected my changes in the docs/sources/v{most_recent_release} folder of the documentation.
• I have reflected my changes in the relevant folders of the two previous k6 versions of the documentation (if still applicable to previous versions).