Representation of charge strengths.
We represent Verilog's charge strengths with the keyword symbols recognized by (vl-cstrength-p x).
BOZO add references to the Verilog-2005 standard, description of what these are.
This is an ordinary defenum.
(defun vl-cstrength-p (x) (declare (xargs :guard t)) (or (eq x ':vl-large) (eq x ':vl-medium) (eq x ':vl-small)))