[texdoc] option names and verbosity

[Karl Berry]

More ideas from this:

Perhaps running with maximum verbosity should tell you where the value
came from (environment or the full texdoc.cnf).  I also find -n very
unintuitive (vs. -v), but we already discussed that.

Also, I think -f could go away and just be included in the normal -v, I
mean -n, output.  It's just reporting the config files it looks for.
Sounds like normal verbose output to me.

k