Append the handler names to the end of the corresponding signal doc.

Task-number: QTBUG-35846
Change-Id: I0d1c067e9eca4c3c28489a074a7f0e33759c000a
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>