Use invariant culture for ToUpper/ToLower

Turkish is quite the language; let's try to prevent any errors down the road for internal/game string case changes.

PKHeX.Core/Legality/Restrictions/WordFilter.cs

@@ -46,7 +46,7 @@ namespace PKHeX.Core
                 return false;
             }
 
-            var msg = message.ToLower();
+            var msg = message.ToLowerInvariant();
             // Check dictionary
             lock (dictLock)
             {

PKHeX.Core/MysteryGifts/MysteryGift.cs

@@ -62,7 +62,7 @@ namespace PKHeX.Core
             _ => null
         };
 
-        public string Extension => GetType().Name.ToLower();
+        public string Extension => GetType().Name.ToLowerInvariant();
         public string FileName => $"{CardHeader}.{Extension}";
         public abstract int Generation { get; }
 

PKHeX.Core/PKM/PKM.cs

@@ -13,7 +13,7 @@ namespace PKHeX.Core
         public static readonly string[] Extensions = PKX.GetPKMExtensions();
         public abstract int SIZE_PARTY { get; }
         public abstract int SIZE_STORED { get; }
-        public string Extension => GetType().Name.ToLower();
+        public string Extension => GetType().Name.ToLowerInvariant();
         public abstract PersonalInfo PersonalInfo { get; }
         public virtual IReadOnlyList<ushort> ExtraBytes => Array.Empty<ushort>();
 

PKHeX.Core/PKM/Util/SpeciesName.cs

@@ -107,7 +107,7 @@ namespace PKHeX.Core
             // All names are uppercase.
             var sb = new System.Text.StringBuilder(nick);
             for (int i = 0; i < sb.Length; i++)
-                sb[i] = char.ToUpper(sb[i]);
+                sb[i] = char.ToUpperInvariant(sb[i]);
             if (language == (int)LanguageID.French)
                 StringConverter4.StripDiacriticsFR4(sb); // strips accents on E and I
 
@@ -134,7 +134,7 @@ namespace PKHeX.Core
                 return nick;
 
             // Gen2: All Caps
-            return nick.ToUpper();
+            return nick.ToUpperInvariant();
         }
 
         /// <summary>

PKHeX.Core/Saves/Util/SaveExtensions.cs

@@ -172,7 +172,7 @@ namespace PKHeX.Core
                 return LoadTemplateInternal(sav);
 
             var di = new DirectoryInfo(templatePath);
-            string path = Path.Combine(templatePath, $"{di.Name}.{sav.PKMType.Name.ToLower()}");
+            string path = Path.Combine(templatePath, $"{di.Name}.{sav.PKMType.Name.ToLowerInvariant()}");
 
             if (!File.Exists(path) || !PKX.IsPKM(new FileInfo(path).Length))
                 return LoadTemplateInternal(sav);

PKHeX.Drawing/Sprites/SpriteUtil.cs

@@ -23,7 +23,7 @@ namespace PKHeX.Drawing
 
         public static Image? GetRibbonSprite(string name)
         {
-            var resource = name.Replace("CountG3", "G3").ToLower();
+            var resource = name.Replace("CountG3", "G3").ToLowerInvariant();
             return (Bitmap?)Resources.ResourceManager.GetObject(resource);
         }
 
@@ -37,14 +37,14 @@ namespace PKHeX.Drawing
         {
             if (max != 4) // Memory
             {
-                var sprite = name.ToLower();
+                var sprite = name.ToLowerInvariant();
                 if (max == value)
                     return sprite + "2";
                 return sprite;
             }
 
             // Count ribbons
-            string n = name.Replace("Count", string.Empty).ToLower();
+            string n = name.Replace("Count", string.Empty).ToLowerInvariant();
             return value switch
             {
                 2 => n + "super",

PKHeX.WinForms/Subforms/PKM Editors/BatchEditor.cs

@@ -27,7 +27,7 @@ namespace PKHeX.WinForms
             CB_Format.Items.Clear();
             CB_Format.Items.Add(MsgAny);
             foreach (Type t in BatchEditing.Types)
-                CB_Format.Items.Add(t.Name.ToLower());
+                CB_Format.Items.Add(t.Name.ToLowerInvariant());
             CB_Format.Items.Add(MsgAll);
 
             CB_Format.SelectedIndex = CB_Require.SelectedIndex = 0;

PKHeX.WinForms/Util/WinFormsUtil.cs

@@ -375,7 +375,7 @@ namespace PKHeX.WinForms
 
         private static void ExportSAV(SaveFile sav, string path)
         {
-            var ext = Path.GetExtension(path).ToLower();
+            var ext = Path.GetExtension(path).ToLowerInvariant();
             var flags = sav.Metadata.GetSuggestedFlags(ext);
 
             try