Implement overwriting correctly

[residuum]

When overwriting existing data in [json-encode], adding an value to an array does not clear the previously stored data.

The output should be:
print: symbol { "id": 1.000000 }
print: symbol { "id": [ 1.000000, 2.000000 ] }
print: symbol { "id": 2.000000 }

But instead is:
print: symbol { "id": 1.000000 }
print: symbol { "id": [ 1.000000, 2.000000 ] }
print: symbol { "id": [ 1.000000, 2.000000 ] }

[residuum]