Move trailing whitespace parsing to a separate element.

I still need to parse the line break at the end of elements.

src/parser/paragraph.rs

@@ -36,8 +36,6 @@ pub fn paragraph<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s st
         |(children, _exit_contents)| !children.is_empty(),
     )(input)?;
 
-    let (remaining, _trailing_whitespace) = trailing_whitespace(remaining)?;
-
     let source = get_consumed(input, remaining);
 
     Ok((remaining, Paragraph { source, children }))