Map keys not sorted

[AZQ1994]

Issue description

Elixir Map changes from sorted map to hashed map when size is over 32.
Current implementation does not sort the keys so it becomes messy with a huge map.

iex(3)> (1..32) |> Map.new(&{&1, &1}) |> Ymlr.document!()
"---\n1: 1\n2: 2\n3: 3\n4: 4\n5: 5\n6: 6\n7: 7\n8: 8\n9: 9\n10: 10\n11: 11\n12: 12\n13: 13\n14: 14\n15: 15\n16: 16\n17: 17\n18: 18\n19: 19\n20: 20\n21: 21\n22: 22\n23: 23\n24: 24\n25: 25\n26: 26\n27: 27\n28: 28\n29: 29\n30: 30\n31: 31\n32: 32\n"
iex(4)> (1..33) |> Map.new(&{&1, &1}) |> Ymlr.document!()
"---\n33: 33\n12: 12\n23: 23\n29: 29\n30: 30\n26: 26\n31: 31\n11: 11\n9: 9\n32: 32\n25: 25\n28: 28\n6: 6\n13: 13\n20: 20\n15: 15\n14: 14\n2: 2\n7: 7\n1: 1\n8: 8\n3: 3\n17: 17\n22: 22\n21: 21\n4: 4\n24: 24\n10: 10\n27: 27\n19: 19\n5: 5\n18: 18\n16: 16\n"