refactor: Change Variables Name in order not to start with _ (#1936)

This generates a huge amount of compilation warnings during Acts Tag bumps in Athena (related only to the nomenclature) that may hide real warnings we should pay attention to.

Absolutely no change in the code behaviour

Core/include/Acts/MagneticField/detail/SmallObjectCache.hpp

@@ -93,18 +93,18 @@ class SmallObjectCache {
     void moveConstruct(void* from, void* to) const override {
       assert(from != nullptr && "Source is null");
       assert(to != nullptr && "Target is null");
-      T* _from = static_cast<T*>(from);
-      /*T* ptr =*/new (to) T(std::move(*_from));
+      T* fromValue = static_cast<T*>(from);
+      /*T* ptr =*/new (to) T(std::move(*fromValue));
     }
 
     void move(void* from, void* to) const override {
       assert(from != nullptr && "Source is null");
       assert(to != nullptr && "Target is null");
 
-      T* _from = static_cast<T*>(from);
-      T* _to = static_cast<T*>(to);
+      T* fromValue = static_cast<T*>(from);
+      T* toValue = static_cast<T*>(to);
 
-      (*_to) = std::move(*_from);
+      (*toValue) = std::move(*fromValue);
     }
   };