F2 on a virtual function call presents a list of overrides in derived
classes. The function declaration of the static type is shown
immediately at the top.

Task-number: QTCREATORBUG-9611

Change-Id: I80ce906fa06272dc9fbd1662cd17500b8c77067f
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>