STENCIL_BITS is not displayed in the stencil state information

[ghost]

Related to #213 where it's ignored for display; but not knowing how many stencil bits exist is a problem.
In my case, I had 0 stencil bits, because the context simply didn't have a stencil buffer, but I didn't catch the issue for a while because number formatting and state-display suggested that it was available.