Prefer single line js docs

[dsherret]

Instead of always doing:

/**
 * Some description.
 */
function myFunc() {
}

It should prefer single line:

/** Some description. */
function myFunc() {
}

Multi-line will occur in either of the two scenarios:

1. When the js doc text starts with a newline (ex. "\nMy description." -- forces a multi-line js doc)
2. When the js doc text spans multiple lines.