vala: Include sender-type parameter to prototype-string of signal-delegates
vala: Include sender-type parameter to prototype-string of signal-delegates

https://bugzilla.gnome.org/show_bug.cgi?id=787521

frida/vala,GNOME/vala,GNOME/vala,frida/vala,GNOME/vala,GNOME/vala,frida/vala,frida/vala,frida/vala