Function build_docs_with_cache 

pub fn build_docs_with_cache(
    config: &DocsConfig,
    config_dir: &Path,
    template_dir: &Path,
    cache: &mut BuildCache,
) -> Result<BuildStats>

Build a documentation site, reusing the supplied BuildCache across invocations.

Always performs a full rebuild. The previous incremental machinery (per-page state hashes, component-bundle signatures, descriptor cache, search-index sig, etc.) was removed because the resulting invariants were complex for a dev-server-only optimization. The rebuild is already fast in practice and a from-scratch run keeps the output guaranteed-consistent with the source.

The cache exists today purely to amortize startup costs that are independent of user-edited content (the syntect highlighter load).