fixed incorrect index computation for ordered collection tail removal

Author: janjanech

SharpDiffLib.Test/Diff/ArrayOfPrimitives.cs

@@ -82,7 +82,7 @@ public void TwoRemoved()
 		{
 			const string diff =
 				"-2:2\r\n" +
-				"-2:3";
+				"-3:3";
 			var @base = new[] { 1, 2, 2, 3 };
 			var changed = new[] { 1, 2 };
 
@@ -211,10 +211,10 @@ public void AllRemoved()
 		{
 			const string diff =
 				"-0:2\r\n" +
-				"-0:2\r\n" +
-				"-0:2\r\n" +
-				"-0:2\r\n" +
-				"-0:2";
+				"-1:2\r\n" +
+				"-2:2\r\n" +
+				"-3:2\r\n" +
+				"-4:2";
 			var @base = new[] { 2, 2, 2, 2, 2 };
 			var changed = new int[] { };
 

SharpDiffLib/algorithms/diff/collection/ordered/OrderedCollectionDiff.cs

@@ -187,7 +187,10 @@ private IDiff<TType> ComputeInternal(IEnumerable<TItemType> @base, IEnumerable<T
 					}
 				}
 				else if (baseHasItem)
+				{
 					ret.Add(new DiffOrderedCollectionRemoved<TItemType>(index, baseItem));
+					index++;
+				}
 				else if (changedHasItem)
 					ret.Add(new DiffOrderedCollectionAdded<TItemType>(index, changedItem));
 				else