[backport#15497] Support ranges arguments in RPC help

Summary:
https://github.com/bitcoin/bitcoin/pull/15497/commits/6b9f45e81bfe7472493b6df66133c929780ef2fb

Depends on D6610

Partial backport of Core PR15497

Test Plan:

ninja

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D6611