fixup! Drop TreeChanges path indexer

Author: nulltoken

LibGit2Sharp.Tests/DiffTreeToTreeFixture.cs

@@ -912,7 +912,7 @@ private void CanHandleTwoTreeEntryChangesWithTheSamePath(SimilarityOptions simil
                 Blob mainContent = OdbHelper.CreateBlob(repo, "awesome content\n" + new string('b', 4096));
                 Blob linkContent = OdbHelper.CreateBlob(repo, "../../objc/Nu.h");
 
-                string path = string.Format("include{0}Nu{0}Nu.h", Path.DirectorySeparatorChar);
+                string path = Path.Combine("include", "Nu", "Nu.h");
 
                 var tdOld = new TreeDefinition()
                     .Add(path, linkContent, Mode.SymbolicLink)