I have made in the past some custom column where i can put pretty much whatever html I want like icons w/ or w/o event.

I would like to replicate this feature on the header (Column Name) row. Right now, my column label is set to
 

but i would like to put html there too.

I'm using the event afterInsertRow to modify my cell value with custom formatter/unformatter.

Is there a similar event after the header row is created?