girparser: Support alias syntax used in GIR version 1.2
girparser: Support alias syntax used in GIR version 1.2

xdave/pvala,GNOME/vala,frida/vala,kamanashisroy/aroop,kamanashisroy/aroop,GNOME/vala,severinh/vala,frida/vala,jessevdk/vala,rvu95/vala,Distrotech/vala,tjol/vala-tjol,rvu95/vala,GNOME/vala,flobrosch/vala-fixes,Distrotech/vala,frida/vala,jessevdk/vala,severinh/vala,playya/vala,spidermonkdust/vala,frida/vala,tjol/vala-tjol,severinh/vala,flobrosch/vala-fixes,playya/vala,GNOME/vala,tjol/vala-tjol,playya/vala,spidermonkdust/vala,kamanashisroy/aroop,spidermonkdust/vala,Distrotech/vala,rvu95/vala,frida/vala,flobrosch/vala-fixes,jessevdk/vala