Added example of C# inline properties (#1464)

This was a really cool & useful trick/feature that I found while
learning C#.

csharp.html.markdown

@@ -672,6 +672,10 @@ on a new line! ""Wow!"", the masses cried";
                     // can also use keyword private
         public string Name { get; set; }
         
+        // Properties also have a special syntax for when you want a readonly property
+        // that simply returns the result of an expression
+        public string LongName => Name + " " + _speed + " speed"; 
+
         // Enum is a value type that consists of a set of named constants
         // It is really just mapping a name to a value (an int, unless specified otherwise).
         // The approved types for an enum are byte, sbyte, short, ushort, int, uint, long, or ulong.