Reformat ES API Reference Documentation

[jrodewig]

Updates the Elasticsearch API documentation to match the Elastic API reference template.

Relates to elastic/docs#937.

• cat APIs (Reformat cat API Reference Documentation #45196)
• Cluster APIs (Reformat Cluster API Reference Documentation  #45197)
• Cross-cluster replication APIs
• Data frame transform APIs
• Document APIs ([DOCS] Reformat Document API Reference Documentation #45365)
• Explore API
• Index APIs ([DOCS] Reformat index API documentation #43765)
• Index lifecycle management API
• Ingest APIs ([DOCS] Reformat ingest API docs #47049)
• Info API
• Licensing APIs
• Machine learning anomaly detection APIs
• Machine learning data frame analytics APIs
• Migration APIs
• Reload Search Analyzers ([DOCS] Reformat reload search analyzers API docs #47824)
• Rollup APIs
• Search APIs (Reformat search API docs #45621)
• Security APIs
• Snapshot lifecycle management API (Reformat snapshot lifecycle policy API docs #45620)
• Watcher APIs

[elasticmachine]

Pinging @elastic/es-docs

[jrodewig]

[docs issue triage]

Leaving open as this is still relevant.