Run config_docs CI check is not run on PRs to only change generated docs (resulting in CI failures)

[alamb]

Describe the bug

There are several times where we broke CI because we directly changed the .md markdown files that are autogenerated, but the CI in the PR did not run

Here are some recent-ish examples PRs that fixed such issues

• Fix function doc CI check #19093
• docs: Fix failing documentation check in CI #17026
• docs: Fix failing CI #17041

To Reproduce

1. Make a PR with a change to a the docs in docs/source/user-guide/sql/scalar_functions.md
2. The CI will pass
3. Commit the PR

However then any PRs that run on code will fail because the autogenerated results will not match what is checked in.

Here is an example of a PR with such a mistake (and I should have known better 🤦 )

• Minor: fix link errors in docs #19088

Expected behavior

let's fix the docs check to automatically run on PRs that change the auto generated files

Additional context

No response

[alamb]

I did make a PR a while ago to try and fix this

• Run config_docs CI check on PRs to change auto generated docs #17046

But it got stake and wasn't merged

[adp2201]

I reproduced this locally.

The failure mode is that a docs-only change to an autogenerated Markdown file under docs/ skips the workflow that contains the generated-doc consistency checks.

What I verified:

• The generated-doc checks live in .github/workflows/rust.yml:
  • Check if configs.md has been modified
  • Check if any of the ***_functions.md has been modified
• That same workflow is gated by paths-ignore for:
  • docs/**
  • **.md

So if a PR changes only generated Markdown such as:

• docs/source/user-guide/configs.md
• docs/source/user-guide/sql/*_functions.md

then rust.yml is skipped, which means the generated-doc drift checks never run.

I also checked the docs PR workflow:

• .github/workflows/docs_pr.yaml runs for docs/**
• it builds the docs, but it does not run ./dev/update_config_docs.sh or ./dev/update_function_docs.sh

So the issue is real: generated docs can be edited directly, the docs workflow still passes, and the sync check is bypassed until a later non-doc PR hits the Rust workflow.

I used a temporary one-line edit to docs/source/user-guide/sql/scalar_functions.md to validate the trigger behavior, then reverted it.