Tier2: fix incorrect return type for JSON_TypeToString()

Should return const char*, function is currently unused so this wasn't noticed until now.

src/public/tier2/jsonutils.h

@@ -111,7 +111,7 @@ inline const char* JSON_TypeToString(const JSONFieldType_e type)
 }
 
 template <class T>
-inline bool JSON_TypeToString(const T& data)
+inline const char* JSON_TypeToString(const T& data)
 {
     return JSON_TypeToString(JSON_ExtractType(data));
 }