Function hextoipv6

hextoipv6(hex): string
convert a 16 byte hexadecimal string to RFC 5952 canonicalized IPv6 address
Parameters
- hex: string
  hexadecimal string of 16 byte IPv6 address
Returns string
IPv6 address string canonicalized by RFC 5952
Description
This function converts a 16 byte hexadecimal string to RFC 5952 canonicalized IPv6 address string.

Example
```
hextoipv6("871020010db8000000000000000000000004") -> "2001:db8::4"
hextoipv6("871020010db8000000000000000000") -> raise exception
hextoipv6("xyzxyzxyzxyzxyzxyzxyzxyzxyzxyzxyzxyz") -> raise exception
```
- Defined in conv_ip.mts:50