Re-add comment to navigation patch

Spigot-Server-Patches/0077-Optimize-Navigation-Listener.patch

@@ -1,4 +1,4 @@
-From 918a65f485c1a865b3a38ecd4e5a879d5bf786aa Mon Sep 17 00:00:00 2001
+From 7a0a329dd1092b98f0951ae49af15c56d210d6d9 Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Tue, 8 Mar 2016 19:13:54 -0500
 Subject: [PATCH] Optimize Navigation Listener
@@ -32,10 +32,10 @@ index 7d794b9..aa18f54 100644
  
      protected abstract Pathfinder a();
 diff --git a/src/main/java/net/minecraft/server/NavigationListener.java b/src/main/java/net/minecraft/server/NavigationListener.java
-index f82ea80..aade479 100644
+index f82ea80..963a0e7 100644
 --- a/src/main/java/net/minecraft/server/NavigationListener.java
 +++ b/src/main/java/net/minecraft/server/NavigationListener.java
-@@ -1,26 +1,32 @@
+@@ -1,26 +1,35 @@
  package net.minecraft.server;
  
 +import java.util.ArrayList; // Paper
@@ -66,13 +66,16 @@ index f82ea80..aade479 100644
 -            for (int k = 0; k < j; ++k) {
 -                NavigationAbstract navigationabstract = anavigationabstract1[k];
 +            */
++            // DO NOT USE AN ITERATOR! This must be a for (;;) to avoid CME.
++            // This is perfectly safe, as additions are ok to be done in this iteration
++            // and Removals are queued instead of immediate.
 +            for (int k = 0; k < this.navigators.size(); ++k) {
 +                NavigationAbstract navigationabstract = this.navigators.get(k);
 +                // Paper end
  
                  if (navigationabstract != null && !navigationabstract.i()) {
                      PathEntity pathentity = navigationabstract.k();
-@@ -55,9 +61,21 @@ public class NavigationListener implements IWorldAccess {
+@@ -55,9 +64,21 @@ public class NavigationListener implements IWorldAccess {
  
      public void a(int i, boolean flag, double d0, double d1, double d2, double d3, double d4, double d5, int... aint) {}