Use Diacritical.Net library for TitleFirstCharacter token

(cherry picked from commit 59ea524e0ce85333779f430b867e93aae366289f)

Closes #9324

src/NzbDrone.Core.Test/OrganizerTests/FileNameBuilderTests/MovieTitleFirstCharacterFixture.cs

@@ -42,6 +42,7 @@ namespace NzbDrone.Core.Test.OrganizerTests.FileNameBuilderTests
         [TestCase("¡Mucha Lucha!", "M", "¡Mucha Lucha!")]
         [TestCase(".hack", "H", "hack")]
         [TestCase("Ütopya", "U", "Ütopya")]
+        [TestCase("Æon Flux", "A", "Æon Flux")]
         public void should_get_expected_folder_name_back(string title, string parent, string child)
         {
             _movie.Title = title;

src/NzbDrone.Core/Organizer/FileNameBuilder.cs

@@ -5,6 +5,8 @@ using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Text.RegularExpressions;
+using Diacritical;
+using DryIoc.ImTools;
 using NLog;
 using NzbDrone.Common.EnsureThat;
 using NzbDrone.Common.Extensions;
@@ -224,13 +226,13 @@ namespace NzbDrone.Core.Organizer
         {
             if (char.IsLetterOrDigit(title[0]))
             {
-                return title.Substring(0, 1).ToUpper().RemoveAccent();
+                return title.Substring(0, 1).ToUpper().RemoveDiacritics()[0].ToString();
             }
 
             // Try the second character if the first was non alphanumeric
             if (char.IsLetterOrDigit(title[1]))
             {
-                return title.Substring(1, 1).ToUpper().RemoveAccent();
+                return title.Substring(1, 1).ToUpper().RemoveDiacritics()[0].ToString();
             }
 
             // Default to "_" if no alphanumeric character can be found in the first 2 positions

src/NzbDrone.Core/Radarr.Core.csproj

@@ -4,6 +4,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Dapper" Version="2.0.143" />
+    <PackageReference Include="Diacritical.Net" Version="1.0.4" />
     <PackageReference Include="Equ" Version="2.3.0" />
     <PackageReference Include="MailKit" Version="3.6.0" />
     <PackageReference Include="Npgsql" Version="7.0.4" />