Add clarifications in the documentation of the `query` command

- Add a statement that the result is always for the latest patch set,
  even if the query matched on an earlier patch set

- Add a link to the change attribute documentation from the JSON
  format option description.

- Add clarification in the change attribute documentation that the
  commit message is of the latest patch set.

- Correct a minor typo

Change-Id: Ie6a825d1d183994926662c0ad8c42ec15f687e51
2 files changed