Describe the bug

Lines ending in commas seem to cause R: Run Selection/Line to send the wrong lines to the console.

To Reproduce

1. Create a file temp.R with the following content:

list(
    1,
    2
)

2. Place cursor on second or third line
3. Use command R: Run Selection/Line

Expected: All four lines are sent to console (if cursor was on second line), or only '2' is sent to console (if cursor was on third line)

Actual: Middle two lines are sent to console:

> 1,
Error: unexpected ',' in "1,"
>     2
[1] 2