TYPO3 Core

Since at least 12.1 the information modal after page slug change
for auto created redirects and/or updated slugs with the option
to revert is no longer shown.

ext:redirects used a hook to inject the event-listener and the
java script language keys, which has been removed with #97451
and replaced by a new PSR-14 event. Due a typo of one removed
hook in the rest file and the extension scanner matcher, it
seems that the internal usage has not been found. Classic chain
of failure in the review process.

The removed hook should be replaced by the event to restore the
old behaviour, which should be doable without hazzle, as implentation
has been and will be internal, thus non breaking.

Further, this can be still considered as bugfix then.