Add PRs from last week to Grafana docs

[heitortsergent]

Bring in the changes we've merged to k6-docs in the last week to the Grafana docs version.

#1385, #1336, #1381.

[heitortsergent]

@ppcano @pablochacin tagging you both here cause there were updates to the xk6-disruptor docs that we merged to k6-docs last week. I tried to bring them over in this PR, if you want to review them and make sure everything looks good. :)

[github-actions]

There's a version of the docs published here:

https://mdr-ci.staging.k6.io/docs/refs/pull/1393/merge

It will be deleted automatically in 30 days.

[jdbaldry]

And VU: grafana/writers-toolkit#366.

It looks like it is commonly misspelt as 'vu' in this file but that's outside of the scope of this PR.
Perhaps lowercase is also an acceptable spelling though?

[heitortsergent]

I think we use lowercase 'vu' when we're referring to the property name in scripts, since that's how it's supposed to be used. It would probably be good to add it as an acceptable spelling as well. 🤓

[jdbaldry]

Ah nice. And that shouldn't be wrapped in backticks to make it code?

Vale doesn't spellcheck code so we wouldn't need the dictionary entry in that case.

[heitortsergent]

Ah, that's a good point. I updated the one instance of vus in the paragraph to use backticks, the other one is in a table and I think we should keep that as regular text... I think most of the other tables where we have properties listed they are just regular text, not code.