Use address reserved for docs in comment

Addresses starting with "192.0.2.", "198.51.100.", or "203.0.113." are reserved for use in documentation and sample configurations. 
The original was some random french IP

Author: taksyon

library/core/src/net/ip_addr.rs

@@ -293,7 +293,7 @@ impl IpAddr {
     ///
     /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
     ///
-    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(80, 9, 12, 3)).is_global(), true);
+    /// assert_eq!(IpAddr::V4(Ipv4Addr::new(192, 0, 2, 3)).is_global(), true);
     /// assert_eq!(IpAddr::V6(Ipv6Addr::new(0, 0, 0x1c9, 0, 0, 0xafc8, 0, 0x1)).is_global(), true);
     /// ```
     #[unstable(feature = "ip", issue = "27709")]