Exclude x-pack docs from CI jobs

[jrodewig]

Problem:
We currently trigger several unneeded CI checks on PRs that only update docs in x-pack/docs/. Example: #99205

Solution:
Update CI jobs that exclude docs/ to also exclude x-pack/docs/.

Note: In the long-term, we should probably move docs in the x-pack directory into docs. I'll handle that in a separate effort/PR.

[elasticsearchmachine]

Pinging @elastic/es-delivery (Team:Delivery)

[jrodewig]

@elasticsearchmachine update branch

[mark-vieira]

LGTM.

@brianseeders we'll want to do something similar in our Buildkite pipelines once we wire up PR triggers.

[jrodewig]

💔 Some backports could not be created

Status	Branch	Result
✅	8.10
✅	8.9
❌	7.17	Could not create pull request: Validation Failed: {"resource":"PullRequest","code":"custom","message":"No commits between elastic:7.17 and jrodewig:backport/7.17/pr-99207"}

Manual backport

To create the backport manually run:

backport --pr 99207

Questions ?

Please refer to the Backport tool documentation