Partial Merge #14726: Use RPCHelpMan for all RPCs

Summary:
fa5e0452e875a7ca6bf6fe61fdd652d341eece40 rpc: Documentation fixups (MarcoFalke)
fa91e8eda541acdb78ca481b74605639f319c108 Use RPCHelpMan for all RPCs (MarcoFalke)

Pull request description:

The resulting documentation should not change unless the type in the oneline-summary was previously incorrect. (E.g. string vs bool)

Tree-SHA512: 4ff355b6a53178f02781e97a7aca7ee1d0d97ff348b6bf5a01caa1c96904ee33c704465fae54c2cd7445097427fd04c71ad3779bb7a7ed886055ef36c1b5a1d0

Partial backport of Core PR14726
Excluded the linter commit.

Reviewer note: the following RPCs have their help changed in another
related PR:

testmempoolaccept
createrawtransaction
createmultisig

Depends on D5567

Test Plan:

ninja
ninja check
./bitcoind
./bitcoin-cli help <RPCs>

Verify help is printed without error.

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, Fabien

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D5548