[trivial/doc] Fix comment type
Summary:
This concludes backport of Core PR18807 [9/9]
https://github.com/bitcoin/bitcoin/pull/18807/commits/9e1cb1adf1800efe429e348650931f2669b0d2c0
Test Plan: ninja
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D9036