Remove * characters from the front of variable docstrings

[Glenn Morris]

I was glad to see the "*" chars finally disappearing in trunk r107813.
However, hasn't some information been lost in the process?

For example, in emacs-24 there is:

(defvar texinfo-column-for-description 32
  "*Column at which descriptions start in a Texinfo menu.")

So, this is something I might want to change.

In trunk, it has no *, so there's no indication it is something I might
want to change.
Shouldn't it (and other defvars with *s) have been converted to defcustoms?