docs(vrl): add new path related documents

[titaneric]

Summary

This PR intends to add the document to describe new VRL function introduced in vectordotdev/vrl#1531, vectordotdev/vrl#1532, vectordotdev/vrl#1533

Vector configuration

How did you test this PR?

cue lint

./website/scripts/cue.sh fmt
CI=true make check-docs

document preview

make preview-build
make serve

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

Closes: vectordotdev/vrl#1348

Notes

• Please read our Vector contributor resources.
• Do not hesitate to use @vectordotdev/vector to reach out to us regarding this PR.
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  • We recommend adding a pre-push hook, please see this template.
  • Alternatively, we recommend running the following locally before pushing to the remote branch:
    • make fmt
    • make check-clippy (if there are failures it's possible some of them can be fixed with make clippy-fix)
    • make test
• After a review is requested, please avoid force pushes to help us review incrementally.
  • Feel free to push as many commits as you want. They will be squashed into one before merging.
  • For example, you can run git merge origin master and git push.
• If this PR introduces changes Vector dependencies (modifies Cargo.lock), please
  run make build-licenses to regenerate the license inventory and commit the changes (if any). More details here.

[pront]

These look reasonable. Worth mentioning that this platform dependent (based on the discussion in one of the PRs).

Let's also wait for a review from @vectordotdev/documentation

[pront]

Check failed: https://github.com/vectordotdev/vector/actions/runs/18287480920/job/52066219808

[titaneric]

cargo vdev check docs
Validating cue files formatting...
/home/runner/work/vector/vector/scripts/check-docs.sh: line 17: /home/runner/work/vector/vector/website/scripts/cue.sh: No such file or directory
Error: command: cd "/home/runner/work/vector/vector" && "/home/runner/work/vector/vector/scripts/check-docs.sh"
failed with exit code: 127

It seems that the cue.sh script is missing on the runner. The cue.sh is located in scripts not in website/scripts

[pront]

cargo vdev check docs
Validating cue files formatting...
/home/runner/work/vector/vector/scripts/check-docs.sh: line 17: /home/runner/work/vector/vector/website/scripts/cue.sh: No such file or directory
Error: command: cd "/home/runner/work/vector/vector" && "/home/runner/work/vector/vector/scripts/check-docs.sh"
failed with exit code: 127

It seems that the cue.sh script is missing on the runner. The cue.sh is located in scripts not in website/scripts

Hi @titaneric, this is a regression from #23951. We will fix this. Thanks.