libvaladoc/api: Signals: Add missing "signal" keyword to signatuers
libvaladoc/api: Signals: Add missing "signal" keyword to signatuers

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