docs: openapi entries for com.atproto.sync.getBlocks + getLatestCommit master
make ci-lexicons on CI regenerates the lex-reference openapi.json and rightly expects the two sync lexicons added in the previous commit to be documented there. The hunk is taken verbatim from CI's own regeneration output rather than a local `make md-lexicons` run, because the local regeneration is environmentally skewed: on this machine it also deletes ~3100 lines of unrelated, still-valid paths (games.* among others) that CI's regeneration keeps, on a tree where CI is otherwise clean. That local-vs-CI md-lexicons divergence predates this branch and deserves its own investigation; it is not made better or worse here. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>