remove some unused code

src/BizHawk.Client.Common/rewind/ZwinderBuffer.cs

@@ -41,8 +41,6 @@ namespace BizHawk.Client.Common
 		/// </summary>
 		public int Count => (_nextStateIndex - _firstStateIndex) & StateMask;
 
-		public float FullnessRatio => Used / (float)Size;
-
 		/// <summary>
 		/// total number of bytes used
 		/// </summary>

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.MenuItems.cs

@@ -994,7 +994,6 @@ namespace BizHawk.Client.EmuHawk
 				Owner = Owner,
 				Location = this.ChildPointToScreen(TasView)
 			}.Show();
-			UpdateChangesIndicator();
 		}
 
 		private void UpdateStateSettings(ZwinderStateManagerSettings settings)
@@ -1013,8 +1012,6 @@ namespace BizHawk.Client.EmuHawk
 				Text = "Savestate History Settings",
 				Owner = Owner
 			}.ShowDialog();
-
-			UpdateChangesIndicator();
 		}
 
 		private void CommentsMenuItem_Click(object sender, EventArgs e)

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.cs

@@ -994,11 +994,6 @@ namespace BizHawk.Client.EmuHawk
 			SplicerStatusLabel.Text = temp;
 		}
 
-		private void UpdateChangesIndicator()
-		{
-			// TODO
-		}
-
 		private void DoTriggeredAutoRestoreIfNeeded()
 		{
 			if (_triggerAutoRestore)