Fix config.ToString (#143)

* Fixed config.ToString indent exception

* Minor warning fix

Author: IgorFedchenko

src/Hocon.Immutable/HoconImmutableLiteral.cs

@@ -19,7 +19,7 @@ public sealed class HoconImmutableLiteral : HoconImmutableElement, IEquatable<Ho
     {
         public static readonly HoconImmutableLiteral Null = HoconImmutableLiteral.Create(null);
 
-        public string Value { get; }
+        public new string Value { get; }
 
         private HoconImmutableLiteral(string value)
         {

src/Hocon.Tests/HoconTests.cs

@@ -395,6 +395,24 @@ public void CanAssignArrayToField()
             //Assert.True(new[] { 1, 2, 3 }.SequenceEqual(Parser.Parse(hocon).GetIntList("a")));
         }
 
+        /// <summary>
+        /// Related issue: https://github.com/akkadotnet/HOCON/issues/108
+        /// </summary>
+        [Fact]
+        public void Config_ToString_Should_work_properly()
+        {
+            var hocon = @"
+a {
+  b = 1
+  c : {
+    d = 2
+  }
+}
+";
+            var config = Parser.Parse(hocon);
+            Record.Exception(() => config.ToString()).Should().BeNull();
+        }
+
         [Fact]
         public void CanConcatenateArray()
         {

src/Hocon/Impl/HoconValue.cs

@@ -1,4 +1,4 @@
-//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
 // <copyright file="HoconValue.cs" company="Hocon Project">
 //     Copyright (C) 2009-2018 Lightbend Inc. <http://www.lightbend.com>
 //     Copyright (C) 2013-2018 .NET Foundation <https://github.com/akkadotnet/hocon>
@@ -682,7 +682,7 @@ internal void ReParent(HoconValue value)
         /// <returns>A HOCON string representation of this <see cref="HoconValue"/>.</returns>
         public override string ToString()
         {
-            return ToString(0, 2);
+            return ToString(1, 2);
         }
 
         /// <inheritdoc />