Fix a regression with headers named after keywords

Fixes https://github.com/mono/CppSharp/issues/1212.

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

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -244,7 +244,7 @@ namespace CppSharp.Generators.CSharp
                 return;
 
             PushBlock(BlockKind.Functions);
-            var parentName = context.TranslationUnit.FileNameWithoutExtension;
+            var parentName = SafeIdentifier(context.TranslationUnit.FileNameWithoutExtension);
 
             var keyword = "class";
             var classes = EnumerateClasses().ToList();
@@ -740,9 +740,8 @@ namespace CppSharp.Generators.CSharp
                 }
             }
 
-            if (@class.IsGenerated && isBindingGen)
+            if (@class.IsGenerated && isBindingGen && @class.IsRefType && !@class.IsOpaque)
             {
-                if (@class.IsRefType && !@class.IsOpaque)
                 bases.Add("IDisposable");
             }
 

tests/Common/interface.h

@@ -0,0 +1 @@
+void Func();