This function allow users to turn an xtable object into a kable
so they can use most of kableExtra's functions with their xtable code without
making too many changes. Note that although I tested many cases and it seems
to work, this function may not be functional in some other cases. I'm not
a regular xtable user and can only provide very limited support for this
function.
You should use this table in the same way as print.xtable. All the options
you provided to this function will be sent to print.xtable. Instead of
printing out the result, this function will return the LaTeX or HTML as
text and a kable object.