The MediaWiki maintenance script maintenance/findHooks.php reads docs/hooks.txt and does stuff with it. T115388 will change hooks.txt to be a YAML file instead plain text. Update the maintenance script so it can handle that.
You probably don't want to wait until T115388 is finished, just hand-modify a few entries, delete the rest, and use that for testing,
Ensuring that MediaWiki core always has access to a YAML parser is a bit beyond the scope of a microtask; you can just assume that the yaml package is always available. This means that your patch cannot be merged; be sure to clarify that in the commit description. (The convention is to put something like [DO NOT MERGE] at the start of the commit description.)