[netif] fix typos in comments (#4520)
diff --git a/src/core/net/netif.cpp b/src/core/net/netif.cpp
index 0d69905..d401d77 100644
--- a/src/core/net/netif.cpp
+++ b/src/core/net/netif.cpp
@@ -70,12 +70,12 @@
     {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}}},
     &Netif::kRealmLocalAllNodesMulticastAddress};
 
-// "ff03:02"
+// "ff03::02"
 const otNetifMulticastAddress Netif::kRealmLocalAllRoutersMulticastAddress = {
     {{{0xff, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02}}},
     &Netif::kLinkLocalAllNodesMulticastAddress};
 
-// "ff02:02"
+// "ff02::02"
 const otNetifMulticastAddress Netif::kLinkLocalAllRoutersMulticastAddress = {
     {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02}}},
     &Netif::kRealmLocalAllRoutersMulticastAddress};