My first inclination is “so what?” events.log is the log of all the events on the Event Bus. It’s supposed to reflect what your openHAB system is doing. Redacting events.log damages it’s very purpose. Instead, I like to recommend How to watch and look through logging instead to filter all your logs to only see those lines that are relevant to what you are actively working on at that time.
But, if you must, openHAB - Filtering event logs shows how to configure the log to exclude lines that match a given regular expression.