Updating HAProxy snapshot documentation v1.5-dev25-51 generated by haproxy-dconv v0.3.1-19

81f5d94 MAJOR: agent: rework the response processing and support additional actions
9b5aecd MEDIUM: cli: add support for enabling/disabling health checks.
2a4b70f MINOR: cli: introduce a new "set server" command
3209123 MEDIUM: server: allow multi-level server tracking