fix typo in tests

Author: yebai

test/copyable_task.jl

@@ -241,6 +241,7 @@
         @test Libtask.consume(tt) === :a
         @test Libtask.consume(tt) === :b
         @test Libtask.consume(tt) === :c
+    end
     @testset "Return produce" begin
         # Test calling a function that does something with the return value of `produce`.
         # In this case it just returns it. This used to error, see