shared_ptr -> std::shared_ptr

This is one of the first commits in a plan to remove all `using namespace std;` lines in the entire codebase as it is considered anti-pattern today.

Minecraft.Client/Common/GameRules/AddEnchantmentRuleDefinition.h

@@ -19,5 +19,5 @@ public:
 
 	virtual void addAttribute(const wstring &attributeName, const wstring &attributeValue);
 
-	bool enchantItem(shared_ptr<ItemInstance> item);
+	bool enchantItem(std::shared_ptr<ItemInstance> item);
 };