Remove uneeded attribute in Charconv

Author: mborland

include/boost/decimal/charconv.hpp

@@ -914,12 +914,12 @@ BOOST_DECIMAL_EXPORT BOOST_DECIMAL_CONSTEXPR auto to_chars(char* first, char* la
 template <typename T>
 struct limits
 {
-    BOOST_DECIMAL_ATTRIBUTE_UNUSED static constexpr int max_chars = boost::decimal::detail::max_string_length_v<T>;
+    static constexpr int max_chars = boost::decimal::detail::max_string_length_v<T>;
 };
 
 #if !(defined(__cpp_inline_variables) && __cpp_inline_variables >= 201606L) && (!defined(_MSC_VER) || _MSC_VER != 1900)
 
-template <typename T> BOOST_DECIMAL_ATTRIBUTE_UNUSED constexpr int limits<T>::max_chars;
+template <typename T> constexpr int limits<T>::max_chars;
 
 #endif