Adds missing reactions to chemical stuff.

- Adds ingestion reaction for food, drinks, and pills.
- Adds injection reaction for syringes.

Content.Server/GameObjects/Components/Chemistry/PillComponent.cs

@@ -11,6 +11,8 @@ using Robust.Shared.GameObjects;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Localization;
+using Robust.Shared.Log;
+using Robust.Shared.Prototypes;
 using Robust.Shared.Serialization;
 using Robust.Shared.ViewVariables;
 
@@ -21,6 +23,7 @@ namespace Content.Server.GameObjects.Components.Chemistry
     public class PillComponent : FoodComponent, IUse, IAfterInteract
     {
         [Dependency] private readonly IEntitySystemManager _entitySystem = default!;
+        [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
 
         public override string Name => "Pill";
 
@@ -45,8 +48,11 @@ namespace Content.Server.GameObjects.Components.Chemistry
         public override void Initialize()
         {
             base.Initialize();
-            
-            _contents = Owner.GetComponent<SolutionContainerComponent>();
+
+            if (!Owner.EnsureComponent(out _contents))
+            {
+                Logger.Error($"Prototype {Owner.Prototype?.ID} had a {nameof(PillComponent)} without a {nameof(SolutionContainerComponent)}!");
+            }
         }
 
         bool IUse.UseEntity(UseEntityEventArgs eventArgs)
@@ -86,13 +92,24 @@ namespace Content.Server.GameObjects.Components.Chemistry
 
             var transferAmount = ReagentUnit.Min(_transferAmount, _contents.CurrentVolume);
             var split = _contents.SplitSolution(transferAmount);
-            if (!stomach.TryTransferSolution(split))
+
+            if (!stomach.CanTransferSolution(split))
             {
                 _contents.TryAddSolution(split);
                 trueTarget.PopupMessage(user, Loc.GetString("You can't eat any more!"));
                 return false;
             }
 
+            // TODO: Account for partial transfer.
+
+            foreach (var (reagentId, quantity) in split.Contents)
+            {
+                if (!_prototypeManager.TryIndex(reagentId, out ReagentPrototype reagent)) continue;
+                split.RemoveReagent(reagentId, reagent.ReactionEntity(trueTarget, ReactionMethod.Ingestion, quantity));
+            }
+
+            stomach.TryTransferSolution(split);
+
             if (_useSound != null)
             {
                 _entitySystem.GetEntitySystem<AudioSystem>()