C#: Add extension types to the db scheme.

Author: michaelnebel

csharp/ql/lib/semmlecode.csharp.dbscheme

@@ -222,7 +222,7 @@ overlayChangedFiles(
          | @using_directive | @type_parameter_constraints | @externalDataElement
          | @xmllocatable | @asp_element | @namespace | @preprocessor_directive;
 
-@declaration = @callable | @generic | @assignable | @namespace;
+@declaration = @callable | @generic | @assignable | @namespace | @extension_type;
 
 @named_element = @namespace | @declaration;
 
@@ -492,6 +492,7 @@ case @type.kind of
 | 32 = @tuple_type
 | 33 = @function_pointer_type
 | 34 = @inline_array_type
+| 35 = @extension_type
   ;
 
 @simple_type = @bool_type | @char_type | @integral_type | @floating_point_type | @decimal_type;
@@ -502,7 +503,7 @@ case @type.kind of
 @value_type = @simple_type | @enum_type | @struct_type | @nullable_type | @int_ptr_type
             | @uint_ptr_type | @tuple_type | @void_type | @inline_array_type;
 @ref_type = @class_type | @interface_type | @array_type | @delegate_type | @null_type
-          | @dynamic_type;
+          | @dynamic_type | @extension_type;
 @value_or_ref_type = @value_type | @ref_type;
 
 typerefs(
@@ -903,7 +904,7 @@ localvar_location(
   unique int id: @local_variable ref,
   int loc: @location ref);
 
-@parameterizable = @callable | @delegate_type | @indexer | @function_pointer_type;
+@parameterizable = @callable | @delegate_type | @indexer | @function_pointer_type | @extension_type;
 
 #keyset[name, parent_id]
 #keyset[index, parent_id]