Update the printing of comments to the new Clang

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

src/AST/Comment.cs

@@ -538,6 +538,7 @@ namespace CppSharp.AST
         A,
         Abstract,
         Addtogroup,
+        Anchor,
         Arg,
         Attention,
         Author,
@@ -623,6 +624,7 @@ namespace CppSharp.AST
         Result,
         Return,
         Returns,
+        Retval,
         Rtfonly,
         Endrtfonly,
         Sa,

src/Generator.Tests/AST/TestAST.cs

@@ -384,7 +384,7 @@ namespace CppSharp.Generator.Tests.AST
                 classTemplate.TemplatedClass.Constructors.First(c => !c.IsCopyConstructor && !c.IsMoveConstructor));
         }
 
-        [Test, Ignore("The new Clang exposes a non-trivial bug in the comments printer, will fix later.")]
+        [Test]
         public void TestComments()
         {
             var @class = AstContext.FindCompleteClass("TestComments");