[REG 4.7->4.8] Code completion for function pointers

Code completion for function pointers automatically completes with brackets:

connect(obj, &QObject::destro <CTRL + Space> completes to: connect(obj, &QObject::destroyed()

Brackets are wrong here. The original Qt Creator code model completes here only signals and the class based on type of <obj>. That would be nice to have back in the future.