Simplified the name of the internal structure.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -40,7 +40,7 @@ namespace CppSharp.Generators.CSharp
             return new string(id.Select(c => char.IsLetterOrDigit(c) ? c : '_').ToArray());
         }
 
-        public static readonly string InternalStruct = Generator.GeneratedIdentifier("_Internal");
+        public static readonly string InternalStruct = Generator.GeneratedIdentifier("Internal");
         public static readonly string InstanceField = Generator.GeneratedIdentifier("instance");
         public static readonly string InstanceIdentifier = Generator.GeneratedIdentifier("Instance");
         public static readonly string PointerAdjustmentIdentifier = Generator.GeneratedIdentifier("PointerAdjustment");

tests/CSharp/CSharp.Tests.cs

@@ -436,7 +436,7 @@ public unsafe class CSharpTests : GeneratorTestFixture
     [Test]
     public unsafe void TestSizeOfDerivesFromTemplateInstantiation()
     {
-        Assert.That(sizeof(DerivesFromTemplateInstantiation.___Internal), Is.EqualTo(sizeof(int)));
+        Assert.That(sizeof(DerivesFromTemplateInstantiation.__Internal), Is.EqualTo(sizeof(int)));
     }
 
     [Test]
@@ -526,12 +526,12 @@ public unsafe class CSharpTests : GeneratorTestFixture
     {
         foreach (var internalType in new[]
             {
-                typeof(CSharp.IndependentFields.___Internal),
+                typeof(CSharp.IndependentFields.__Internal),
-                typeof(CSharp.DependentValueFields.___Internalc__S_DependentValueFields__b),
+                typeof(CSharp.DependentValueFields.__Internalc__S_DependentValueFields__b),
                 //typeof(CSharp.DependentValueFields.Internal_float),
-                typeof(CSharp.DependentPointerFields.___Internal),
+                typeof(CSharp.DependentPointerFields.__Internal),
                 //typeof(CSharp.DependentValueFields.Internal_Ptr),
-                typeof(CSharp.HasDefaultTemplateArgument.___Internalc__S_HasDefaultTemplateArgument__I___S_IndependentFields__I)
+                typeof(CSharp.HasDefaultTemplateArgument.__Internalc__S_HasDefaultTemplateArgument__I___S_IndependentFields__I)
             })
         {
             var independentFields = internalType.GetFields();