For OpenLineBelow, add newline to the end of the line of the current …

[JasonBrownDeveloper]

For OpenLineBelow, add newline to the end of the line of the current selection, instead of the line below the selection, for a more consistent history

Given the following buffer:

Line Zero\n$
$

Pressing the o key on (zero indexed) line one, results in the following history:

• 1561858 1 0 1561866 2 +0.0|L +0.1|i +0.2|n +0.3|e +0.4| +0.5|Z +0.6|e +0.7|r +0.8|o +0.9|\n
  1 1561872 - +2.0|\n
  +2.0|Line Two

After the patch, pressing the o key, the history would look like the following, which would match if i and <ret> had been pressed on line one.

• 1561858 1 0 1561866 2 +0.0|L +0.1|i +0.2|n +0.3|e +0.4| +0.5|Z +0.6|e +0.7|r +0.8|o +0.9|\n
  1 1561872 - +1.0|\n
  +2.0|Line Two