tools: command records, Git group - NOTES as bullets, one exit line per cause, examples and prohibitions (#142)

Files changed:
- CHANGES.md
- VERSION
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/cli_contract.py
- tools/chemenu/commands/cite_cmd.py
- tools/chemenu/commands/dist_cmd.py
- tools/chemenu/commands/docs_verify.py
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/eval_cmd.py
- tools/chemenu/commands/git_publish.py
- tools/chemenu/commands/index_build.py
- tools/chemenu/commands/instructions_cmd.py
- tools/chemenu/commands/links_cmd.py
- tools/chemenu/commands/lint.py
- tools/chemenu/commands/log_append.py
- tools/chemenu/commands/migrate_cmd.py
- tools/chemenu/commands/new_page.py
- tools/chemenu/commands/page_ops.py
- tools/chemenu/commands/provenance_cmd.py
- tools/chemenu/commands/raw_cmd.py
- tools/chemenu/commands/review_cmd.py
- tools/chemenu/commands/run_budget.py
- tools/chemenu/commands/search.py
- tools/chemenu/commands/task_cmd.py
- tools/chemenu/commands/touch.py
- tools/chemenu/commands/types_cmd.py
- tools/chemenu/commands/upload_cmd.py
- tools/chemenu/commands/upstream_cmd.py
- tools/chemenu/commands/version_cmd.py
- tools/chemenu/commands/work_cmd.py
- tools/chemenu/commands/xref.py
- tools/chemenu/tests/test_cli_contract.py
- tools/chemenu/tests/test_docs_verify.py

tools/README.md

@@ -86,7 +86,10 @@ bound at import time - `KB_DIR` and friends follow whatever `ROOT` currently is.
    <cmd> -h`, the index (`wikitool -h`, and the top of
    [CONTRACT.md](CONTRACT.md)), and CONTRACT.md's generated `#### <path>`
    section all render from - see `cli_contract.py`'s own module docstring for
-   the record's shape. `docs verify` fails in both directions - a command with
+   the record's shape, and the `CommandRecord` docstring for how its prose is
+   written (NOTES as present-tense bullets, one `Failure` per cause with its
+   reaction, copyable EXAMPLES, NEVER, SEE ALSO, and no "why" - that goes into
+   a comment next to the code). `docs verify` fails in both directions - a command with
    no record and a `GROUPS` entry naming no real command are equally reported -
    and also checks that every non-hidden flag appears in the record's SYNOPSIS.
    Then regenerate the copy: `wikitool docs contract --apply`. Write the