Indexing a tree by path yields different result with trailing slash

When a slash is included when indexing into a tree to a subtree, the resulting TreeEntry has a path with a duplicated last path part.

using System.Text;
using LibGit2Sharp;

var path = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());

using var repo = new Repository(Repository.Init(path, isBare: true));

var bytes = Encoding.UTF8.GetBytes("Hello, World!");

var blob = repo.ObjectDatabase.CreateBlob(new MemoryStream(bytes));

var td = new TreeDefinition();
td.Add("some/deeply/nested/file", blob, Mode.NonExecutableFile);

var tree = repo.ObjectDatabase.CreateTree(td);

var withSlash = tree["some/deeply/"].Path;
var withoutSlash = tree["some/deeply"].Path;

Console.WriteLine(withSlash);       // some/deeply/deeply
Console.WriteLine(withoutSlash);    // some/deeply

I was seeing this across Linux and Windows, on versions 0.31 and 0.32 and .NET 10 and Framework 4.8

使用提供的 TreeDefinition 和樹索引器範例重現此差異，比較針對 "some/deeply/" 和 "some/deeply" 回傳的路徑。追蹤已索引子樹的 TreeEntry 路徑建構，並新增一個涵蓋這兩個輸入的回歸測試。當帶有結尾斜線的索引會回傳與不帶斜線的等效路徑相同的非重複路徑時，即表示完成。