Update docs-build.yml

[theletterf]

This PR adds support for Vale docs linting to the repository. Linting only triggers when Markdown files inside the docs folder are edited. Vale linting never blocks pull requests. For more information, refer to Vale linter.

Contributes to https://github.com/elastic/docs-content-internal/issues/660

[elasticsearchmachine]

Pinging @elastic/core-docs (Team:Docs)

[theletterf]

@shainaraskas @szabosteve Which folders should we include?

[shainaraskas]

lgtm but let's please hold until tue so I can give my group a formal heads up

[shainaraskas]

how do these two interact with include-paths? assuming we could probably just kill them from the config (or does this control when the workflow is triggered at all?)

[theletterf]

Good question! These are two different filtering layers that work independently:

• path-pattern / path-pattern-ignore are inputs to the docs-builder reusable workflow. They control which changed files trigger the workflow (or get passed to the docs build). So path-pattern: docs/** with path-pattern-ignore: docs/changelog/**/*.yaml means "run when docs files change, but ignore changelog YAML files."
• include-paths is a Vale-specific input. It controls which files actually get linted once the workflow is running. It's a second, independent filter applied only to the Vale linting step.

They're complementary, not redundant. path-pattern gates the whole workflow; include-paths narrows what Vale looks at within that run.

You could technically remove path-pattern-ignore if the only purpose was to skip linting those files, since include-paths already excludes anything outside docs/reference/** and docs/extend/**. But path-pattern-ignore also prevents the entire workflow from triggering on changelog-only PRs, which saves CI time.

[szabosteve]

LGTM!