Melee refactor (#10897)

Co-authored-by: metalgearsloth <metalgearsloth@gmail.com>

Content.Shared/CombatMode/Events/CombatModeSystemMessages.cs

@@ -0,0 +1,19 @@
+using Content.Shared.Targeting;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.CombatMode
+{
+    public static class CombatModeSystemMessages
+    {
+        [Serializable, NetSerializable]
+        public sealed class SetTargetZoneMessage : EntityEventArgs
+        {
+            public SetTargetZoneMessage(TargetingZone targetZone)
+            {
+                TargetZone = targetZone;
+            }
+
+            public TargetingZone TargetZone { get; }
+        }
+    }
+}