Throw error when trying to emit a non-existing signal.
Throw error when trying to emit a non-existing signal.

closes #6017

mcanders/godot,Shockblast/godot,tomreyn/godot,vnen/godot,Faless/godot,NateWardawg/godot,RebelliousX/Go_Dot,RebelliousX/Go_Dot,ageazrael/godot,honix/godot,Max-Might/godot,Valentactive/godot,ex/godot,Brickcaster/godot,Faless/godot,honix/godot,Zylann/godot,n-pigeon/godot,tomreyn/godot,josempans/godot,Zylann/godot,MrMaidx/godot,Shockblast/godot,pkowal1982/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,ex/godot,ex/godot,ex/godot,jejung/godot,josempans/godot,godotengine/godot,Shockblast/godot,BastiaanOlij/godot,MrMaidx/godot,godotengine/godot,sanikoyes/godot,n-pigeon/godot,morrow1nd/godot,josempans/godot,okamstudio/godot,Paulloz/godot,ZuBsPaCe/godot,vkbsb/godot,ficoos/godot,MrMaidx/godot,Zylann/godot,Marqin/godot,vkbsb/godot,Brickcaster/godot,RandomShaper/godot,guilhermefelipecgs/godot,morrow1nd/godot,Faless/godot,MarianoGnu/godot,ficoos/godot,Valentactive/godot,mcanders/godot,NateWardawg/godot,Zylann/godot,ageazrael/godot,pkowal1982/godot,sanikoyes/godot,RandomShaper/godot,FateAce/godot,Brickcaster/godot,ficoos/godot,mcanders/godot,BastiaanOlij/godot,akien-mga/godot,groud/godot,Faless/godot,akien-mga/godot,josempans/godot,okamstudio/godot,vkbsb/godot,guilhermefelipecgs/godot,pkowal1982/godot,BastiaanOlij/godot,Max-Might/godot,FateAce/godot,Brickcaster/godot,NateWardawg/godot,okamstudio/godot,pkowal1982/godot,morrow1nd/godot,jejung/godot,firefly2442/godot,groud/godot,okamstudio/godot,vnen/godot,ex/godot,RebelliousX/Go_Dot,Faless/godot,okamstudio/godot,RandomShaper/godot,Valentactive/godot,BastiaanOlij/godot,Brickcaster/godot,akien-mga/godot,honix/godot,pkowal1982/godot,Marqin/godot,MrMaidx/godot,MarianoGnu/godot,tomreyn/godot,mcanders/godot,okamstudio/godot,ZuBsPaCe/godot,MarianoGnu/godot,firefly2442/godot,morrow1nd/godot,DmitriySalnikov/godot,Max-Might/godot,tomreyn/godot,Marqin/godot,exabon/godot,ficoos/godot,exabon/godot,josempans/godot,Max-Might/godot,okamstudio/godot,Shockblast/godot,akien-mga/godot,zicklag/godot,Faless/godot,BastiaanOlij/godot,vnen/godot,RebelliousX/Go_Dot,ageazrael/godot,RebelliousX/Go_Dot,josempans/godot,jejung/godot,NateWardawg/godot,DmitriySalnikov/godot,sanikoyes/godot,MrMaidx/godot,ageazrael/godot,okamstudio/godot,godotengine/godot,exabon/godot,Zylann/godot,Brickcaster/godot,Paulloz/godot,honix/godot,ZuBsPaCe/godot,sanikoyes/godot,ficoos/godot,Zylann/godot,morrow1nd/godot,godotengine/godot,sanikoyes/godot,FateAce/godot,Marqin/godot,pkowal1982/godot,exabon/godot,Max-Might/godot,okamstudio/godot,Paulloz/godot,godotengine/godot,firefly2442/godot,DmitriySalnikov/godot,vkbsb/godot,sanikoyes/godot,Shockblast/godot,okamstudio/godot,RebelliousX/Go_Dot,akien-mga/godot,MrMaidx/godot,MarianoGnu/godot,morrow1nd/godot,RandomShaper/godot,MarianoGnu/godot,zicklag/godot,ZuBsPaCe/godot,vkbsb/godot,ageazrael/godot,RandomShaper/godot,vkbsb/godot,Paulloz/godot,exabon/godot,sanikoyes/godot,Shockblast/godot,BastiaanOlij/godot,n-pigeon/godot,NateWardawg/godot,NateWardawg/godot,DmitriySalnikov/godot,FateAce/godot,ex/godot,Marqin/godot,ageazrael/godot,Faless/godot,honix/godot,groud/godot,josempans/godot,NateWardawg/godot,DmitriySalnikov/godot,Zylann/godot,RandomShaper/godot,Zylann/godot,sanikoyes/godot,Shockblast/godot,ZuBsPaCe/godot,firefly2442/godot,Paulloz/godot,Paulloz/godot,Marqin/godot,ficoos/godot,zicklag/godot,akien-mga/godot,godotengine/godot,zicklag/godot,NateWardawg/godot,ZuBsPaCe/godot,MarianoGnu/godot,Valentactive/godot,firefly2442/godot,DmitriySalnikov/godot,pkowal1982/godot,RandomShaper/godot,godotengine/godot,josempans/godot,n-pigeon/godot,Valentactive/godot,guilhermefelipecgs/godot,zicklag/godot,MarianoGnu/godot,vnen/godot,groud/godot,Brickcaster/godot,Faless/godot,zicklag/godot,Valentactive/godot,groud/godot,MarianoGnu/godot,guilhermefelipecgs/godot,vkbsb/godot,vnen/godot,FateAce/godot,n-pigeon/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,pkowal1982/godot,DmitriySalnikov/godot,akien-mga/godot,n-pigeon/godot,guilhermefelipecgs/godot,vnen/godot,jejung/godot,groud/godot,guilhermefelipecgs/godot,ZuBsPaCe/godot,godotengine/godot,tomreyn/godot,akien-mga/godot,ex/godot,firefly2442/godot,firefly2442/godot,honix/godot,jejung/godot,exabon/godot,Shockblast/godot,FateAce/godot,Max-Might/godot,firefly2442/godot,mcanders/godot,vnen/godot,Paulloz/godot,mcanders/godot,n-pigeon/godot,ex/godot,vnen/godot,ageazrael/godot,Valentactive/godot,jejung/godot,vkbsb/godot,Valentactive/godot,NateWardawg/godot,ZuBsPaCe/godot