scide: sc_editor: include parenthesis in regionAroundCursor()

When evaluating a region, the evaluated code excludes the parenthesis
which define the region. If they are included instead, we avoid a
parse error when evaluating array shortcut notations like `(1..3)`.

Signed-off-by: Yvan Volochine <yvan.volochine@gmail.com>
Merge pull request #892 from gusano/topic/current_region_fix

scide: sc_editor: include parenthesis in regionAroundCursor()