Adding code samples for custom events

Author: AarDavMax

articles/azure-monitor/app/opentelemetry-add-modify.md

@@ -1949,7 +1949,7 @@ Attaching custom dimensions to logs can be accomplished using a [message templat
 
 Logback, Log4j, and java.util.logging are [autoinstrumented](#logs). Attaching custom dimensions to your logs can be accomplished in these ways:
 
-* [Log4j 2.0 MapMessage](https://logging.apache.org/log4j/2.x/log4j-api/apidocs/org/apache/logging/log4j/message/MapMessage.html) (a `MapMessage` key of `"message"` is captured as the log message)
+* [Log4j 2.0 MapMessage](https://logging.apache.org/log4j/2.0/javadoc/log4j-api/org/apache/logging/log4j/message/MapMessage.html) (a `MapMessage` key of `"message"` is captured as the log message)
 * [Log4j 2.0 Thread Context](https://logging.apache.org/log4j/2.x/manual/thread-context.html)
 * [Log4j 1.2 MDC](https://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/MDC.html)