Fixes the four findings of the sixth review: `snapshot remove` with
`--local-only`, the two comma-chained permission lists, six undefined terms,
and the sentence about an unfinished snapshot in the local index.
Then reads every sentence of `README.md`, `ARCHITECTURE.md`,
`docs/DATAMODEL.md`, `docs/REPOSTRUCTURE.md` and the comments in
`config.example.yml` against the code for four faults: a command's needs or
behaviour stated without regard to a flag, a false absolute, three or more
things chained with commas, and a technical word not defined on first use.
Each sentence changed is listed on the pull request.
The help string of `snapshot remove --dry-run` now says it needs no
permission to delete.
Model: fable-5-1