[Meta] Stack monitoring documentation issues

[robbavey]

This meta issue will collect a list of known issues with the documentation of stack monitoring of Logstash

• [Doc]Stack Monitoring metricbeat logstash module security setup is incorrect #14661

• [DOCS] Logstash Monitoring behaves strangely when monitoring.cluster_uuid is not specified.  #15122

• Also our overview page says legacy but we listed up all possible collection types: https://www.elastic.co/guide/en/logstash/current/configuring-logstash.html

• And there is a discrepancy between our docs. This monitoring.enabled: false sounds like turning off legacy but we don’t allow when enabling legacy monitoring…https://www.elastic.co/guide/en/logstash/current/monitoring-with-metricbeat.html#disable-default

• MONITORING_ENABLED example is not good in docker config page example, https://www.elastic.co/guide/en/logstash/current/docker-config.html#docker-env-config

[dedemorton]

Just wanted to note that I am planning to update the stack monitoring docs to include Elastic Agent collection. The tracking issue is here: elastic/observability-docs#2602.

[mashhurs]

Relative case: #15122