Добавил возможность написать моноширинным подчерком хе-хе

Content.Client/ADT/UserInterface/RichText/MonospaceTag.cs

@@ -0,0 +1,38 @@
+using System.Linq;
+using Robust.Client.Graphics;
+using Robust.Client.ResourceManagement;
+using Robust.Client.UserInterface.RichText;
+using Robust.Shared.IoC;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Utility;
+
+namespace Content.Client.ADT.UserInterface.RichText;
+
+public sealed class MonospaceTag : IMarkupTag
+{
+    public const string MonospaceFont = "Monospace";
+
+    [Dependency] private readonly IResourceCache _resourceCache = default!;
+    [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
+
+    public string Name => "mono";
+
+    /// <inheritdoc/>
+    public void PushDrawContext(MarkupNode node, MarkupDrawingContext context)
+    {
+        var font = FontTag.CreateFont(
+            context.Font,
+            node,
+            _resourceCache,
+            _prototypeManager,
+            MonospaceFont
+        );
+        context.Font.Push(font);
+    }
+
+    /// <inheritdoc/>
+    public void PopDrawContext(MarkupNode node, MarkupDrawingContext context)
+    {
+        context.Font.Pop();
+    }
+}

Content.Client/Paper/UI/PaperWindow.xaml.cs

@@ -10,6 +10,7 @@
 using Robust.Shared.Utility;
 using Robust.Client.UserInterface.RichText;
 using Robust.Shared.Input;
+using Content.Client.ADT.UserInterface.RichText;
 
 namespace Content.Client.Paper.UI
 {
@@ -43,7 +44,8 @@ public sealed partial class PaperWindow : BaseWindow
             typeof(BulletTag),
             typeof(ColorTag),
             typeof(HeadingTag),
-            typeof(ItalicTag)
+            typeof(ItalicTag),
+            typeof(MonospaceTag),
         };
 
         public event Action<string>? OnSaved;