fix(bot): throw error if user requests incompatible list options

current behaviour is to silently ignore the incompatible ones, but this will make it more obvious as to why what they're trying to do is not working

PluralKit.Bot/Commands/Lists/ContextListExt.cs

@@ -76,11 +76,18 @@ public static class ContextListExt
         if (ctx.MatchFlag("with-displayname", "wdn"))
             p.IncludeDisplayName = true;
 
-        // Always show the sort property, too
+        // Always show the sort property, too (unless this is the short list)
-        if (p.SortProperty == SortProperty.LastSwitch) p.IncludeLastSwitch = true;
+        if (p.Type != ListType.Short)
-        if (p.SortProperty == SortProperty.LastMessage) p.IncludeLastMessage = true;
+        {
+            if (p.SortProperty == SortProperty.DisplayName) p.IncludeDisplayName = true;
             if (p.SortProperty == SortProperty.MessageCount) p.IncludeMessageCount = true;
             if (p.SortProperty == SortProperty.CreationDate) p.IncludeCreated = true;
+            if (p.SortProperty == SortProperty.LastSwitch) p.IncludeLastSwitch = true;
+            if (p.SortProperty == SortProperty.LastMessage) p.IncludeLastMessage = true;
+        }
+
+        // Make sure the options are valid
+        p.AssertIsValid();
 
         // Done!
         return p;

PluralKit.Bot/Commands/Lists/ListOptions.cs

@@ -11,7 +11,20 @@ namespace PluralKit.Bot;
 
 public class ListOptions
 {
-    public SortProperty SortProperty { get; set; } = SortProperty.Name;
+    private SortProperty? _sortProperty { get; set; }
+    public SortProperty SortProperty
+    {
+        get => _sortProperty ?? SortProperty.Name;
+        set
+        {
+            if (_sortProperty != null)
+                throw new PKError("Cannot sort in multiple ways at the same time. Please choose only one sorting method.");
+
+            _sortProperty = value;
+        }
+    }
+
+
     public bool Reverse { get; set; }
 
     public PrivacyLevel? PrivacyFilter { get; set; } = PrivacyLevel.Public;
@@ -148,6 +161,27 @@ public static class ListOptionsExt
                 // Lastly, add a by-name fallback order for collisions (generally hits w/ lots of null values)
                 .ThenBy(g => g.NameFor(ctx), culture);
     }
+
+    public static void AssertIsValid(this ListOptions opts)
+    {
+        if (opts.Type == ListType.Short)
+        {
+            var hasMultipleIncluded = new[] {
+                opts.IncludeMessageCount,
+                opts.IncludeLastSwitch,
+                opts.IncludeLastMessage,
+                opts.IncludeCreated,
+                opts.IncludeAvatar,
+                opts.IncludePronouns,
+                opts.IncludeDisplayName,
+            }.Sum(x => Convert.ToInt32(x)) > 0;
+            
+            if (hasMultipleIncluded)
+                throw new PKError("The short list does not support showing items from multiple flags. Try using the full list instead.");
+        }
+
+        // the check for multiple *sorting* property flags is done in SortProperty setter
+    }
 }
 
 public enum SortProperty