sync
correct typos in comment and add missing asterix

closes ocamllabs/rwo-comments#2258
Fixes #2197
Merge branch 'master' of git://github.com/realworldocaml/examples
Fix Menhir JSON examples to be JSON-compliant (object keys must be strings)

closes ocamllabs/rwo-comments#2217
update back-end examples for ocamllabs/rwo-comments#2222 and ocamllabs/rwo-comments#2252
update for d4ea7a681e9be56fea5065636226664bbe0a7736
update benchmark for ocamllabs/rwo-comments#2222
Renumber parts in subtyping.topscript
Fixes #2205
Merge pull request #4 from lpw25/address-comments

Address comments