rm 'using'

GUI/Model/Detector/ResolutionFunctionCatalog.h

@@ -22,8 +22,6 @@ class ResolutionFunctionItem;
 
 class ResolutionFunctionCatalog {
 public:
-    using BaseItem = ResolutionFunctionItem;
-
     // Do not change the numbering! It is serialized!
     enum class Type : uint8_t { None = 0, Gaussian = 1 };