Support option to preserve text indent when wrapping markdown lists

[jfroelich]

similar to the technique of deciding whether or not to add an extra space and an asterisk on the next line when splitting the first line of a block comment. when splitting a bullet point, we have to decide whether the text should have extra leading whitespace. the lead whitespace up to the bullet point is working fine. it is the extra 2 spaces on the next line of the bulletpoint in addition.

Should this:

/**
 * * list item that is really| long
 */

become this

/**
 * * list item that is really|
 * long
 */

or this?

/**
 * * list item that is really|
 *   long
 */