Fix ConstantOfShape compilation for clang.

include/aidge/operator/ConstantOfShape.hpp

@@ -39,12 +39,13 @@ enum class ConstantOfShapeAttr {
    */
   Value,
 };
-
+} // namespace Aidge
 namespace {
   template <>
   const char *const EnumStrings<Aidge::ConstantOfShapeAttr>::data[] = {"value"};
-  }
-  
+ } //namespace
+
+  namespace Aidge {
 
 /**
  * @brief This operator's purpose is to generate a tensor of shape given via