Feature Request: add --echo-rowno and --echo-row options

[jqnatividad]

It'd be great if these two "echo" options can be added that is functionally symmetric to the existing --echo-column <column_name>, whereby:

• --echo-rowno
  print the rowno of the selected row to stdout
• --echo-row
  print the selected record as a CSV to stdout. If --no-headers is on, the printed CSV will have no headers. Otherwise, it will have the header. It will also use the specified --delimiter.

As a stretch goal, --echo-row could have a <format> argument, where format could be:

• csv (default)
• jsonl
• json