Fix minor typos in xk6-disruptor docs

[al3xandrugroza]

This pull request corrects two minor typos in the xk6-disruptor documentation.

What?

Fix typo: Lear -> Learn.

In the following sentence only one period is needed.
Refer to [Expose your application](https://grafana.com/docs/k6/latest/testing-guides/injecting-faults-with-xk6-disruptor/expose--your-application/) section for instructions on how to make your application available from outside the Kubernetes cluster..

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 made my changes in the docs/sources/k6/next folder of the documentation.
• I have reflected my changes in the docs/sources/k6/v{most_recent_release} folder of the documentation.

[heitortsergent]

@jdbaldry @robbymilo could you please help take a look and see why zizmor is failing on this PR? 🤔

[jdbaldry]

I think it's known to have some trouble on forks but the security team are working on it.

I think you can ignore it in this case.

[heitortsergent]

Ok, thanks @jdbaldry! 🙇

And thanks @al3xandrugroza for opening the PR and contributing to the k6 docs! 🙇