removal of \@rmfamilyhook and related 2020 internal hooks #746
Description
Around 2020 LaTeX had a couple of font hooks, i.e., \XXfamilyhook where XX is rm,sf,tt or default. Those got replaced by proper hooks, named rmfamily in \rmfamily etc, but the corresponding old hook macros have been kept around (but no longer used).
In the upcoming LaTeX release we want to finally drop also the dummy definitions for \@rmfamilyhook, \@sffamilyhook, \@ttfamilyhook and \@defaultfamilyhook, so references to them in ctex may have to be checked.