efl_text_cursor: correct class description name of simple class

Summary:
Name of `Efl_Class_Description` should be eo-style class name.
Please check there is no segmentation fault on Test code below.

Thanks to @woohyun for reporting and test case.

Test Plan:
```
//mcs test.cs -out:test.exe `pkg-config --libs efl-mono`

using System;

class Program
{
   public static void Main() {
      Efl.All.Init(Efl.Csharp.Components.Ui);

      Efl.Ui.Win win = new Efl.Ui.Win(null);
      Efl.Ui.Box box = new Efl.Ui.Box(win);
      Efl.Ui.Textbox tb = new Efl.Ui.Textbox(win);

      Efl.Ui.Button btn = new Efl.Ui.Button(box);
      btn.Text = "Click Me!";
      btn.ClickedEvent += (s, e) =>
      {
         Efl.Text.Cursor cur1, cur2;

         tb.GetSelectionCursors(out cur1, out cur2);
         cur1.SetPosition(3);
         cur2.SetPosition(7);
      };

      box.Pack(btn);
      box.Pack(tb);

      win.SetContent(box);
      win.SetSize(new Eina.Size2D(200, 400));
      Efl.Ui.Config.Run();
      Efl.All.Shutdown();
   }
}
```

Reviewers: woohyun, ali.alzyod, bu5hm4n

Reviewed By: woohyun

Subscribers: cedric, #reviewers, #committers, woohyun

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D11115

src/lib/evas/canvas/efl_text_cursor.c

@@ -21,7 +21,7 @@ struct _Evas_Textblock_Selection_Iterator
 
 typedef struct _Evas_Textblock_Selection_Iterator Evas_Textblock_Selection_Iterator;
 
-EFL_CLASS_SIMPLE_CLASS(efl_text_cursor, "efl_text_cursor", EFL_TEXT_CURSOR_CLASS)
+EFL_CLASS_SIMPLE_CLASS(efl_text_cursor, "Efl.Text.Cursor", EFL_TEXT_CURSOR_CLASS)
 
 EOLIAN static void
 _efl_text_cursor_position_set(Eo *obj EINA_UNUSED, Efl_Text_Cursor_Data *pd, int position)