Add REDIS_OPT_PREFER_UNSPEC (#1101)

Add REDIS_OPT_PREFER_UNSPEC

See: #1099, #1096

Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>

Author: michael-grunder

README.md

@@ -124,7 +124,7 @@ There are several flags you may set in the `redisOptions` struct to change defau
 | --- | --- |
 | REDIS\_OPT\_NONBLOCK | Tells hiredis to make a non-blocking connection. |
 | REDIS\_OPT\_REUSEADDR | Tells hiredis to set the [SO_REUSEADDR](https://man7.org/linux/man-pages/man7/socket.7.html) socket option |
-| REDIS\_OPT\_PREFER\_IPV4<br>REDIS\_OPT\_PREFER_IPV6 | Informs hiredis to either prefer `IPV4` or `IPV6` when invoking [getaddrinfo](https://man7.org/linux/man-pages/man3/gai_strerror.3.html).  Note that both of the options may be set at once, which will cause hiredis to spcify `AF_UNSPEC` in the getaddrinfo call, which means both `IPV4` and `IPV6` addresses will be searched simultaneously. | 
+| REDIS\_OPT\_PREFER\_IPV4<br>REDIS\_OPT\_PREFER_IPV6<br>REDIS\_OPT\_PREFER\_IP\_UNSPEC | Informs hiredis to either prefer IPv4 or IPv6 when invoking [getaddrinfo](https://man7.org/linux/man-pages/man3/gai_strerror.3.html).  `REDIS_OPT_PREFER_IP_UNSPEC` will cause hiredis to specify `AF_UNSPEC` in the getaddrinfo call, which means both IPv4 and IPv6 addresses will be searched simultaneously.<br>Hiredis prefers IPv4 by default. |
 | REDIS\_OPT\_NO\_PUSH\_AUTOFREE | Tells hiredis to not install the default RESP3 PUSH handler (which just intercepts and frees the replies).  This is useful in situations where you want to process these messages in-band. |
 | REDIS\_OPT\_NOAUOTFREEREPLIES | **ASYNC**: tells hiredis not to automatically invoke `freeReplyObject` after executing the reply callback. |
 | REDIS\_OPT\_NOAUTOFREE | **ASYNC**: Tells hiredis not to automatically free the `redisAsyncContext` on connection/communication failure, but only if the user makes an explicit call to `redisAsyncDisconnect` or `redisAsyncFree` |

hiredis.h

@@ -156,6 +156,7 @@ struct redisSsl;
 #define REDIS_OPT_REUSEADDR 0x02
 #define REDIS_OPT_PREFER_IPV4 0x04
 #define REDIS_OPT_PREFER_IPV6 0x08
+#define REDIS_OPT_PREFER_IP_UNSPEC (REDIS_OPT_PREFER_IPV4 | REDIS_OPT_PREFER_IPV6)
 
 /**
  * Don't automatically free the async object on a connection failure,