Clean up parameters intro.

[Rowlando13]

Made the Parameters' first few sections cleaner and more concise.

[tachyondecay]

Looks good overall—some of the lines aren’t wrapped, not sure how much this matters.

[Rowlando13]

Fixed as @tachyondecay suggested. I generally don't split rst files at the 80 character limit since you can just use the text wrap setting. Documentation is long form writing so 80 characters does not make a lot of sense.