[texdoc] option parsing

[Karl Berry]

The texdoc --help message seems out of sync with reality (or something).

$ texdoc -v 9 symbols
texdoc version: 0.4+ svn r25  # obviously -v was interpreted as --version

$ texdoc --verbosity 9 symbols
texdoc error: unknown option: --verbosity
...

$ texdoc -V
texdoc error: unknown option: -V
Usage:  texdoc  -h, --help | -V, --version | -f, --files | [option(s)] name(s)
...
    -V, --version           Print the version of the program.
....
    -v, --verbosity=N       Set verbosity level to N.


Also, I strongly suggest that when there is an unknown option, texdoc
prints
  Try `texdoc --help' for more information.
instead of the whole lengthy help message.  (As with, e.g., cp --foo.)