Codechange: Replace old non-standard attributes with C++17/20 standard attributes.

src/newgrf_industries.h

@@ -57,7 +57,7 @@ struct IndustriesResolverObject : public ResolverObject {
 				TownScopeResolver *tsr = this->GetTown();
 				if (tsr != nullptr) return tsr;
 			}
-			FALLTHROUGH;
+			[[fallthrough]];
 
 			default:
 				return ResolverObject::GetScope(scope, relative);