"Warning: Parameter 1 to DiscordHooks::onArticleRevisionVisibilitySet() expected to be a reference, value given"

[Dinoguy1000]

This error is produced on changing the visibility of a revision (specifically on changing the visibility of the revision text, though I'm sure it would happen on changing the visibility of the summary or actor name, or any combination of them). Comparing the parameters of onArticleRevisionVisibilitySet() to other functions, the former uses &$title while e.g. onArticleUndelete() instead uses Title $title (but looking at more functions suggests there's no real set pattern to what exactly is passed in for the page title of the action performed, I'm guessing because the hooks used just aren't consistent either?)

Note that this was encountered on MW 1.31, so changes in subsequent versions of MW may have fixed this (the parameter references are identical between the REL1_31 and main branches of this extension).