refactor: rewrite the histories filter function to supports both include and exclude modes (#690)

Signed-off-by: leo <longshuang@msn.cn>

src/Converters/FilterModeConverters.cs

@@ -0,0 +1,22 @@
+using Avalonia.Data.Converters;
+using Avalonia.Media;
+
+namespace SourceGit.Converters
+{
+    public static class FilterModeConverters
+    {
+        public static readonly FuncValueConverter<Models.FilterMode, IBrush> ToBorderBrush =
+            new FuncValueConverter<Models.FilterMode, IBrush>(v => 
+            {
+                switch (v)
+                {
+                    case Models.FilterMode.Included:
+                        return Brushes.Green;
+                    case Models.FilterMode.Excluded:
+                        return Brushes.Red;
+                    default:
+                        return Brushes.Transparent;
+                }
+            });
+    }
+}