rpc: Assert that RPCArg names are equal to CRPCCommand ones (mining)

Summary:
This is a backport of core#19717 [2/4]
https://github.com/bitcoin/bitcoin/pull/19717/commits/faaa46dc204d6d714f71dbc6f0bf02215dba0f0f

Note: the double \n in rpc_generate.py is required because of D7184

Depends on D10145 and D10149

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10146