Handle DreamObjectSavefile in the in operator (OpenDreamProject#2471)

Author: wixoaGit

OpenDream.sln.DotSettings

@@ -41,6 +41,7 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=cmptext/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=compiletimereadonly/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=copytext/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=datums/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Debuggee/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=deciseconds/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=fcopy/@EntryIndexedValue">True</s:Boolean>

OpenDreamRuntime/Objects/Types/DreamList.cs

@@ -827,7 +827,7 @@ public override void AddValue(DreamValue value) {
         var immutableOverlay = _appearanceSystem.AddAppearance(overlayAppearance ?? MutableAppearance.Default);
         overlayAppearance?.Dispose();
 
-        //after UpdateApparance is done, the atom is set with a new immutable appearance containing a hard ref to the overlay
+        //after UpdateAppearance is done, the atom is set with a new immutable appearance containing a hard ref to the overlay
         //only /mutable_appearance handles it differently, and that's done in DreamObjectImage
         _atomManager.UpdateAppearance(_owner, appearance => {
             GetOverlaysList(appearance).Add(immutableOverlay);
@@ -1567,8 +1567,8 @@ public override int FindValue(DreamValue value, int start = 1, int end = 0) {
     }
 }
 
-// Savefile Dir List - always sync'd with Savefiles currentDir. Only stores keys.
-internal sealed class SavefileDirList(DreamObjectDefinition listDef, DreamObjectSavefile backedSaveFile) : DreamList(listDef, 0) {
+// Savefile Dir List - always synced with Savefiles currentDir. Only stores keys.
+public sealed class SavefileDirList(DreamObjectDefinition listDef, DreamObjectSavefile backedSaveFile) : DreamList(listDef, 0) {
     public override DreamValue GetValue(DreamValue key) {
         if (!key.TryGetValueAsInteger(out var index))
             throw new Exception($"Invalid index on savefile dir list: {key}");
@@ -1577,6 +1577,10 @@ public override DreamValue GetValue(DreamValue key) {
         return new DreamValue(backedSaveFile.CurrentDir.Keys.ElementAt(index - 1));
     }
 
+    public override bool ContainsValue(DreamValue value) {
+        return value.TryGetValueAsString(out var str) && backedSaveFile.CurrentDir.ContainsKey(str);
+    }
+
     public override List<DreamValue> GetValues() {
         return EnumerateValues().ToList();
     }