Rustdoc ignores a newline in one-line doc comments

[lifthrasiir]

Paraphrased from my earlier post. Given the following code:

/// This is a doc comment with two paragraphs.
///
/// Not actually.
pub fn a() {
}

/**
 * This is a doc comment with two paragraphs.
 *
 * Really.
 */
pub fn b() {
}

...rustdoc produces two paragraphs for b but one paragraph for a (behaves as if there are no empty lines). I have assumed that it was by design until now, but @brson considered it to be a bug.