** New function 'cl-type-of'

[minad]

This function is like 'type-of' except that it sometimes returns
a more precise type. For example, for nil and t it returns 'null'
and 'boolean' respectively, instead of just 'symbol'.

(Emacs 30)

[minad]

I think this API is a bit special (why is it in cl-* even?). We should only implement it if requested and needed by another package.