[Kinflou]

Checks five reference pages that core#197 lists as not reviewed in depth against the default branches of core, generation, runtime and cli, and fixes what had drifted.

• C ABI (reference/c-abi.md): the vector counts are now 76 cases (handshake 13, framing-jsonrpc 26) since runtime#76. The revision the page was checked at is updated, and a note says runtime#76 raised the core cost of the jsonrpc@1 decode. Functions, structs, codes, flags and constants match comline.h. comline_connection_size/init are still absent, as the page says.
• Generator protocol: html is listed as a renderer id, alongside comline-doc-html. notes says what built versions lack. Added that serve_stdio/respond refuse a request whose protocol or IR format doesn't match.
• Conformance: a new "Comparing as JSON" section covers the exact-decimal number rule (runtime#72), string escapes and JSON inside frames. --timeout covers every case together.
• inspect: documents the IR format stamp check: a store in another format is refused with exit 2.
• doc:
  • doc open also picks html when it's already rendered.
  • --version writes to the resolved version's folder, not the spec.
  • [doc] renderer replaces the built-ins for every format but json.
  • nav.yml includes the overview and the changelog.
  • The header has a Compare link.
  • Theme persistence (window.name, ?theme=) and page titles are described.
  • Built-version notes now cover both what's missing (headers and wire summaries).
  • Exit code 2 for the format-stamp refusal.

Refs ComlineProject/core#197