Changed default Multi Rename shortcut to align with default Rename shortcut

CHANGED: Default Multi Rename shortcut changed (Shift+F9 -> Shift+F2) to align with the default Rename shortcut (F2).

Default Rename shortcut was previously moved from F9 to F2.
However default Multi Rename shortcut remained to be Shift+F9.
This patch changes it too Shift+F2.

Authored By: rade
Reviewed By: asensi, martinkostolny, nmel
Edited By: nmel

Differential Revision: https://phabricator.kde.org/D11903