add mixing categories to chem guidebook (#22566)

Content.Shared/Chemistry/Reaction/MixingCategoryPrototype.cs

@@ -1,4 +1,5 @@
 using Robust.Shared.Prototypes;
+using Robust.Shared.Utility;
 
 namespace Content.Shared.Chemistry.Reaction;
 
@@ -11,4 +12,16 @@ public sealed partial class MixingCategoryPrototype : IPrototype
     /// <inheritdoc/>
     [IdDataField]
     public string ID { get; } = default!;
+
+    /// <summary>
+    /// A locale string used in the guidebook to describe this mixing category.
+    /// </summary>
+    [DataField(required: true)]
+    public LocId VerbText;
+
+    /// <summary>
+    /// An icon used to represent this mixing category in the guidebook.
+    /// </summary>
+    [DataField(required: true)]
+    public SpriteSpecifier Icon = default!;
 }