Enforce template syntax typename over class

(cherry picked from commit 87f5fb0691)

include/godot_cpp/templates/safe_refcount.hpp

@@ -57,7 +57,7 @@ namespace godot {
 	static_assert(sizeof(SafeFlag) == sizeof(bool)); \
 	static_assert(alignof(SafeFlag) == alignof(bool));
 
-template <class T>
+template <typename T>
 class SafeNumeric {
 	std::atomic<T> value;
 
@@ -195,7 +195,7 @@ public:
 
 #else
 
-template <class T>
+template <typename T>
 class SafeNumeric {
 protected:
 	T value;