Function expect_number_or_null

pub fn expect_number_or_null(
    token: Option<Result<Token<'_>, DeserializeError>>,
) -> Result<Option<Number>, DeserializeError>

Expects a Token::ValueString, Token::ValueNumber or Token::ValueNull.

If the value is a string, it MUST be Infinity, -Infinity or Nan. If the value is a number, it is returned directly