ux: add a placeholder for filter-change TextBox (#2565)

Author: love-linger

src/Resources/Locales/en_US.axaml

@@ -1009,6 +1009,7 @@
   <x:String x:Key="Text.WorkingCopy.Conflicts.Resolved" xml:space="preserve">FILE CONFLICTS ARE RESOLVED</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseMine" xml:space="preserve">USE MINE</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseTheirs" xml:space="preserve">USE THEIRS</x:String>
+  <x:String x:Key="Text.WorkingCopy.FilterChanges" xml:space="preserve">Filter Changes...</x:String>
   <x:String x:Key="Text.WorkingCopy.IncludeUntracked" xml:space="preserve">INCLUDE UNTRACKED FILES</x:String>
   <x:String x:Key="Text.WorkingCopy.NoCommitHistories" xml:space="preserve">NO RECENT INPUT MESSAGES</x:String>
   <x:String x:Key="Text.WorkingCopy.NoCommitTemplates" xml:space="preserve">NO COMMIT TEMPLATES</x:String>

src/Resources/Locales/zh_CN.axaml

@@ -1013,6 +1013,7 @@
   <x:String x:Key="Text.WorkingCopy.Conflicts.Resolved" xml:space="preserve">文件冲突已解决</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseMine" xml:space="preserve">使用 MINE</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseTheirs" xml:space="preserve">使用 THEIRS</x:String>
+  <x:String x:Key="Text.WorkingCopy.FilterChanges" xml:space="preserve">查找变更...</x:String>
   <x:String x:Key="Text.WorkingCopy.IncludeUntracked" xml:space="preserve">显示未跟踪文件</x:String>
   <x:String x:Key="Text.WorkingCopy.NoCommitHistories" xml:space="preserve">没有提交信息记录</x:String>
   <x:String x:Key="Text.WorkingCopy.NoCommitTemplates" xml:space="preserve">没有可应用的提交信息模板</x:String>

src/Resources/Locales/zh_TW.axaml

@@ -1013,6 +1013,7 @@
   <x:String x:Key="Text.WorkingCopy.Conflicts.Resolved" xml:space="preserve">檔案衝突已解決</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseMine" xml:space="preserve">使用我方版本 (ours)</x:String>
   <x:String x:Key="Text.WorkingCopy.Conflicts.UseTheirs" xml:space="preserve">使用對方版本 (theirs)</x:String>
+  <x:String x:Key="Text.WorkingCopy.FilterChanges" xml:space="preserve">搜尋变更...</x:String>
   <x:String x:Key="Text.WorkingCopy.IncludeUntracked" xml:space="preserve">顯示未追蹤檔案</x:String>
   <x:String x:Key="Text.WorkingCopy.NoCommitHistories" xml:space="preserve">沒有提交訊息記錄</x:String>
   <x:String x:Key="Text.WorkingCopy.NoCommitTemplates" xml:space="preserve">沒有可套用的提交訊息範本</x:String>

src/Views/WorkingCopy.axaml

@@ -33,6 +33,7 @@
                  CornerRadius="12"
                  Text="{Binding Filter, Mode=TwoWay}"
                  BorderBrush="{DynamicResource Brush.Border2}"
+                 Watermark="{DynamicResource Text.WorkingCopy.FilterChanges}"
                  VerticalContentAlignment="Center">
           <TextBox.InnerLeftContent>
             <Path Width="14" Height="14"