I had a previous PR (#21674) where I updated the inline documentation to fix a parameter type mismatch, but I just realized that I updated the wrong method. The old PR isn't wrong per-se, however, I need to actually fix my original problem.
Summary
This PR updates the type of the LayoutHelper::render() method's $displayData parameter to be mixed. This parameter commonly accepts arrays for various layout objects (i.e. search tools).
@brianteeman @mbabker cc