Method push

include/sol/reference.hpp:385–391

		}

		int push(lua_State* L_) const noexcept {
#if SOL_IS_ON(SOL_SAFE_STACK_CHECK)
			luaL_checkstack(L_, 1, "not enough Lua stack space to push this reference value");
#endif // make sure stack doesn't overflow
			lua_rawgeti(L_, LUA_REGISTRYINDEX, ref);
			return 1;
		}

		void pop(lua_State* L_, int n = 1) const noexcept {
			lua_pop(L_, n);