Enhanced doc for option parameters

[BurdetteLamar]

This separate-page write-up for option parameters is meant to:

• Provide examples for all option parameters.
• Provide link targets for all other references to option parameters.

The sense of this page is to explicate what the option-creating methods can do.

The sense of the (evolving) tutorial page is to explicate what the user can do.

This PR is big, so if you'd like to review just part of it, please say so in a comment.

[olleolleolle]

I read the whole thing, now, and I made small notes where I could not immediately get what was going on. Mostly because I'm not perfectly familiar with all the options, and I learned things while reading it.

Thanks so much for doing this change. It was this month that I needed to have good documentation on how optional options were to be written - and now you've gone and fixed that!

[BurdetteLamar]

I read the whole thing, now, and I made small notes where I could not immediately get what was going on. Mostly because I'm not perfectly familiar with all the options, and I learned things while reading it.

Thanks so much for doing this change. It was this month that I needed to have good documentation on how optional options were to be written - and now you've gone and fixed that!

Glad if it helps. My current mission is to make important tools more accessible. An earlier project was doc for CSV. Now comes doc for OptionParser.

[olleolleolle]

Each of my inline questions was answered, and the one edit was committed. This is ready to go, as far as I can see.

[BurdetteLamar]

@olleolleolle, are you a Ruby committer? If so, you can merge this.