add comment for future semconv 1.33.0 update

Author: SylvainJuge

instrumentation/log4j/log4j-appender-2.17/library/src/main/java/io/opentelemetry/instrumentation/log4j/appender/v2_17/internal/LogEventMapper.java

@@ -31,6 +31,7 @@
 public final class LogEventMapper<T> {
 
   // copied from CodeIncubatingAttributes
+  // TODO: remove duplication when updating to semconv 1.33.0 or later
   private static final AttributeKey<String> CODE_FILEPATH =
       AttributeKey.stringKey("code.file.path");
   private static final AttributeKey<String> CODE_FUNCTION =