util/TruncateString: rename CopyString() to CopyTruncateString()

src/java/String.cxx

@@ -38,7 +38,7 @@ Java::String::CopyTo(JNIEnv *env, jstring value,
 	if (p == nullptr)
 		return nullptr;
 
-	char *result = CopyString(buffer, p, max_size);
+	char *result = CopyTruncateString(buffer, p, max_size);
 	env->ReleaseStringUTFChars(value, p);
 	return result;
 }