Refactor serialization copying to use source generators (#19412)

Content.Server/Chemistry/ReagentEffectConditions/ReagentThreshold.cs

@@ -11,7 +11,7 @@ namespace Content.Server.Chemistry.ReagentEffectConditions
     ///     This can also trigger on -other- reagents, not just the one metabolizing. By default, it uses the
     ///     one being metabolized.
     /// </summary>
-    public sealed class ReagentThreshold : ReagentEffectCondition
+    public sealed partial class ReagentThreshold : ReagentEffectCondition
     {
         [DataField("min")]
         public FixedPoint2 Min = FixedPoint2.Zero;