Add troubleshooting section to infra monitoring

docs/en/observability/handle-no-results-found-message.asciidoc

@@ -1,5 +1,5 @@
 [[handle-no-results-found-message]]
-= Fix "no results found" message
+= Understanding "no results found" message
 
 To correctly render visualizations in the {observability} UI,
 all metrics used by the UI must be present in the collected data.

docs/en/observability/index.asciidoc

@@ -78,7 +78,9 @@ include::monitor-infra/inspect-metric-anomalies.asciidoc[leveloffset=+2]
 
 include::monitor-infra/configure-metrics-sources.asciidoc[leveloffset=+2]
 
-include::handle-no-results-found-message.asciidoc[leveloffset=+2]
+include::troubleshooting-infra.asciidoc[leveloffset=+2]
+
+include::handle-no-results-found-message.asciidoc[leveloffset=+3]
 
 include::monitor-infra/metrics-reference.asciidoc[leveloffset=+2]
 

docs/en/observability/troubleshooting-infra.asciidoc

@@ -0,0 +1,19 @@
+[[troubleshooting-infrastructure-monitoring]]
+= Troubleshooting
+
+Learn how to troubleshoot common issues on your own or ask for help.
+
+[discrete]
+[[troubleshooting-infra-support]]
+=== Elastic Support
+
+We offer a support experience unlike any other.
+Our team of professionals 'speak human and code' and love making your day.
+https://www.elastic.co/subscriptions[Learn more about subscriptions].
+
+[discrete]
+[[troubleshooting-infra-forum]]
+=== Discussion forum
+
+For other questions and feature requests,
+visit our https://discuss.elastic.co/c/observability[discussion forum].