yam --quotes doesn't work for floats (and probably others)

```
~/src/misc/yam/pkg/yam/testdata/format yam-quotes* ≡
❯ cat ./quotes_float.yaml 
quotes:
  version: 5.12

~/src/misc/yam/pkg/yam/testdata/format yam-quotes* ≡
❯ yam --quote '.package.version' ./quotes_float.yaml

~/src/misc/yam/pkg/yam/testdata/format yam-quotes* ≡
❯ cat ./quotes_float.yaml
quotes:
  version: 5.12
```


Found debugging with cue.