Fix various typos

Found via `codespell -q 3 -S ./thirdparty,*.po,./DONORS.md -L ackward,ang,ans,ba,beng,cas,childs,childrens,dof,doubleclick,expct,fave,findn,gird,hist,inh,inout,leapyear,lod,nd,numer,ois,ony,paket,ro,seeked,sinc,switchs,te,uint,varn,vew`

editor/rename_dialog.cpp

@@ -527,7 +527,7 @@ String RenameDialog::_postprocess(const String &subject) {
 		// To Lowercase
 		result = result.to_lower();
 	} else if (case_id == 2) {
-		// To Upercase
+		// To Uppercase
 		result = result.to_upper();
 	}