Wrong end_line on last paragraph node #276

Running the following code:

var commonmark = require('commonmark');
var reader = new commonmark.DocParser();
var readme =
     "X\n" +
     "---\n" +
     "Bar\n"

var parsed = reader.parse(readme);
console.log(parsed);

Results in the following:

{ t: 'Document',
start_line: 1,
start_column: 1,
end_line: 1,
children:
[ { t: 'Header',
start_line: 1,
start_column: 1,
end_line: 2,
inline_content: [Object],
level: 2,
children: [] },
{ t: 'Paragraph',
start_line: 3,
start_column: 1,
end_line: 2,
inline_content: [Object],
children: [] } ] }

On the last child, the end_line is smaller than the start_line. That doesn't seem right. In fact, it should be 1 larger than it is.