Merging keys then deserializing `.nan`, `.inf`, or `-.inf` into a `f32` or `f64` results in an error.

Merging keys then deserializing .nan, .inf, or -.inf into a f32 or f64 results in an error.
I have not tested without the serde_yaml feature as that as my program uses that feature.
Not merging keys does not produce this issue, but my program needs to merge keys, unlike the example below.

---

Minimum example

Manifest

[package]
name = "yaml-merge-keys_issue"
version = "0.1.0"

[dependencies]
serde_yaml = "0.8"
yaml-merge-keys = { version = "0.5", features = ["serde_yaml"] }

main.rs

fn main() {
    let value: Result<f32, _> = serde_yaml::from_value(
        yaml_merge_keys::merge_keys_serde(serde_yaml::from_str(".nan").unwrap()).unwrap(),
    );
    println!("value: {:?}", value);
}

Output: value: Err(Message("invalid type: string \".nan\", expected f32", None))
Expected: value: Ok(NaN)
Cargo package of example: yaml-merge-keys_issue.zip