Fix parsing on lines ending with a comment

.gitignore

@@ -21,6 +21,9 @@ bld/
 [Bb]in/
 [Oo]bj/
 
+# JetBrains Rider
+.idea/
+
 # Visual Studio 2015 cache/options directory
 .vs/
 # Uncomment if you have tasks that create the project's static files in wwwroot

ValveKeyValue/ValveKeyValue.Test/Text/CommentOnEndOfTheLine.cs

@@ -0,0 +1,28 @@
+using System.Linq;
+using System.Text;
+using NUnit.Framework;
+
+namespace ValveKeyValue.Test
+{
+    class CommentOnEndOfTheLine
+    {
+        [Test]
+        public void CanHandleCommentOnEndOfTheLine()
+        {
+            var text = new StringBuilder();
+            text.Append(@"""test_kv""" + "\n");
+            text.Append("{" + "\n");
+            text.Append("//" + "\n");
+            text.Append(@"""test""	""hello""" + "\n");
+            text.Append("}" + "\n");
+
+            var data = KVSerializer.Create(KVSerializationFormat.KeyValues1Text).Deserialize(text.ToString());
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(data.Children.Count(), Is.EqualTo(1));
+                Assert.That((string)data["test"], Is.EqualTo("hello"));
+            });
+        }
+    }
+}

ValveKeyValue/ValveKeyValue/Deserialization/KV1TokenReader.cs

@@ -106,7 +106,7 @@ KVToken ReadComment()
                 sb.Append(next);
             }
 
-            if (sb[^1] == '\r')
+            if (sb.Length > 0 && sb[^1] == '\r')
             {
                 sb.Remove(sb.Length - 1, 1);
             }