Here is my struct

```
#[derive(Serialize, Deserialize, Clone, Copy, Debug, JsonSchema)]
pub struct Position {
    x: SignedDecimal,
    y: SignedDecimal,
}

#[derive(Serialize, Deserialize, Clone, Copy, Debug, JsonSchema)]
pub struct SignedDecimal {
    value: Decimal256,
    sign:  bool,
}

```

An example output of the default schema looks like this:

```
{
    "x": { "value": "1.5", "sign": true },
    "y": { "value": "1.5", "sign": true }
}

```

What I want it to look like is this:

```
{
    "x": "1.5",
    "y": "1.5"
}

```

But I can't seem to get the Schemars macros to do what I want.
I've tried many things, like this for example:

```
#[derive(Serialize, Deserialize, Clone, Copy, Debug, JsonSchema)]
#[schemars(schema_with = "String")]
pub struct SignedDecimal {
    value: Decimal256,
    sign:  bool,
}

```

Ideally I am not using any additional macros on the Position struct, and instead just modifying the SignedDecimal struct. All of the relevant String impls have been defined, I just can't make the macro do what I want.