Merge #14056: Docs: Fix help message typo optiona -> optional

Summary:
7d0a8ad3103200145ab2e73368c3b8345a66c15d Docs: Fix help message typo optiona -> optional (Ben Woosley)

Pull request description:

Tree-SHA512: 1812b45d912769f11280e3f72d7c8bd273f6d151797d5d32d21cd5a3bbe8725515406494291953be7a9afc02a2cef23bed1930ac3638f8118c0d8346ee8d6332

Backport of Core PR14056
https://github.com/bitcoin/bitcoin/pull/14056/

Test Plan:

ninja check
./bitcoind
./bitcoin-cli help walletprocesspsbt
./bitcoin-cli help walletcreatefundedpsbt
arc lint --everything

Confirm there are no instances of optiona.

Reviewers: deadalnix, Fabien, jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Reviewed By: Fabien, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D4962