Run otel.io checks and codegen in any language as a prereq to release

[lmolkova]

See

• [editorial] Fix invalid #instrument-advice anchors #1316
• [editorial] Anchor IDs do not exist in v1.27 of docs #1313

We may be able to run otel.io checks manually, see #1313 (comment)

Also, we could detect issues like #1031 and #1314 if we run codegen in more-or-less any language prior to release.

We can consider starting such checks manually until the release process is automated.