ice: fix comment about relay preference

BUG=webrtc:13195

Change-Id: I86b0ff259cec7d2dc95ba5d7ae1022aca4dcb01c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/233260
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Reviewed-by: Jonas Oreland <jonaso@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35123}

api/candidate.cc

diff --git a/api/candidate.cc b/api/candidate.cc
index 2da2468..4d17256 100644
--- a/api/candidate.cc
+++ b/api/candidate.cc
@@ -101,7 +101,9 @@
   //      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   // NIC Type - Type of the network adapter e.g. 3G/Wifi/Wired.
   // Addr Pref - Address preference value as per RFC 3484.
-  // local preference =  (NIC Type << 8 | Addr_Pref) - relay preference.
+  // local preference =  (NIC Type << 8 | Addr_Pref) + relay preference.
+  // The relay preference is based on the number of TURN servers, the
+  // first TURN server gets the highest preference.
 
   int addr_pref = IPAddressPrecedence(address_.ipaddr());
   int local_preference =