[texdoc] --help tweaks

[Karl Berry]

I suggest that the --help message have an extra line saying what the
program does.  Also, I don't think it's worth the text to bother listing
the help/version/files options in the synopsis.  Suggestion:

Usage: texdoc [OPTION]... [NAME]...

texdoc tries to find appropriate TeX documentation for the specified NAME(s).
With no NAME, it can print configuration information (-f, --files);
the usual --help and --version options are also accepted.

Options:
  -h, --help ...  [I suggest indenting by two spaces to minimize space used]


And finally, I suggest ending like this (minimizing line breaks):


Environment: PAGER, BROWSER, PDFVIEWER, PSVIEWER, DVIVIEWER.
Files: <texmf>/texdoc/texdoc.cnf files; see the -f option.

texdoc home page: <http://tug.org/texdoc/>


FWIW ...