FluentValue::into_number may cause issues with decimal conversions

[kazimuth]

impl FluentValue {
    pub fn into_number<S: ToString>(v: S) -> Result<Self, ParseFloatError> {
        f64::from_str(&v.to_string()).map(|_| FluentValue::Number(v.to_string()))
    }
    // ...
}

https://github.com/projectfluent/fluent-rs/blob/master/fluent-bundle/src/types.rs#L32

f64 has limited precision which may not accurately represent an input number, for instance if I'm using a d128 to represent currency.

It might be worth writing a custom parser that validates inputs are usable numbers without modifying them.

[alerque]

This issue is a duplicate of #337 (and also #214). That issue is of course later than this one, but since it has some suggestions of a fix I think I'll close this version no discussion continues elsewhere. I would suggest subscribing to #337 if you want to be notified when this is fixed.