Print the documentation of an item named by an odoc reference, e.g. `switchdocs show Stdlib.List.map`, rendered as Markdown. This is the reference-resolution half of `odoc link` run standalone over the whole switch: scan `<prefix>/doc` for the include dirs and a linked-unit index, parse and resolve the reference with Odoc_xref2.Ref_tools against the switch's .odoc files, then load the owning unit's .odocl and walk its Lang tree to the item's doc comment and render it via the odoc.markdown backend. The owning unit among same-named candidates (e.g. two Stdlib.odocl) is selected by matching the resolved identifier's key suffix, so the loaded unit stays consistent with what the reference resolved into. Module targets fall back to their signature's top-comment when the declaration itself is undocumented. See DESIGN_SHOW.md. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>