Added support for 16-bit wide characters (char16_t).

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

src/Generator/Generators/CLI/CLIMarshal.cs

@@ -211,6 +211,7 @@ namespace CppSharp.Generators.CLI
                     return true;
                 case PrimitiveType.Bool:
                 case PrimitiveType.Char:
+                case PrimitiveType.Char16:
                 case PrimitiveType.WideChar:
                 case PrimitiveType.SChar:
                 case PrimitiveType.UChar:

src/Generator/Generators/CSharp/CSharpMarshal.cs

@@ -244,8 +244,6 @@ namespace CppSharp.Generators.CSharp
                         return true;
                     }
                     goto default;
-                case PrimitiveType.Char16:
-                    return false;
                 case PrimitiveType.Bool:
                     if (Context.MarshalKind == MarshalKind.NativeField)
                     {
@@ -728,8 +726,6 @@ namespace CppSharp.Generators.CSharp
                         return true;
                     }
                     goto default;
-                case PrimitiveType.Char16:
-                    return false;
                 case PrimitiveType.Bool:
                     if (Context.MarshalKind == MarshalKind.NativeField)
                     {

tests/Common/Common.Tests.cs

@@ -826,4 +826,13 @@ This is a very long string. This is a very long string. This is a very long stri
             Assert.That(testProperties.RefToPrimitiveInSetter, Is.EqualTo(value));
         }
     }
+
+    [Test]
+    public void TestReturnChar16()
+    {
+        using (var foo = new Foo())
+        {
+            Assert.That(foo.ReturnChar16(), Is.EqualTo('a'));
+        }
+    }
 }

tests/Common/Common.cpp

@@ -74,6 +74,11 @@ int Foo::fooPtr()
     return 1;
 }
 
+char16_t Foo::returnChar16()
+{
+    return 'a';
+}
+
 Foo2::Foo2() {}
 
 Foo2 Foo2::operator<<(signed int i)

tests/Common/Common.h

@@ -108,6 +108,7 @@ public:
     bool operator ==(const Foo& other) const;
 
     int fooPtr();
+    char16_t returnChar16();
 };
 
 // HACK: do not move these to the cpp - C++/CLI is buggy and cannot link static fields initialised in the cpp