Bump pinned doc-builder workflow SHA to 23dc84b (#4617)
Picks up huggingface/doc-builder#810, which restores method names,
anchors, signatures and the Parameters/Returns labels in the `.md`
(llms / plain-text) export of `[[autodoc]]` pages.
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
