Docs: Asciidoctor compatibility (#2567) (#2568) (#2569)

Fixes all build errors I found when trying to build the docs using
asciidoctor.

docs/copied-from-beats/monitoring/monitoring-beats.asciidoc

@@ -37,7 +37,6 @@ information, see
 configured the {es} output and want to send {beatname_uc} monitoring events to
 the same {es} cluster, specify the following minimal configuration:
 +
---
 ["source","yml",subs="attributes"]
 --------------------
 monitoring:
@@ -46,11 +45,11 @@ monitoring:
     username: {beat_monitoring_user}
     password: somepassword
 --------------------
-
++
 If you configured a different output, such as {ls} or you want to send {beatname_uc}
 monitoring events to a separate {es} cluster (referred to as the _monitoring cluster_),
 you must specify additional configuration options. For example:
-
++
 ["source","yml",subs="attributes"]
 --------------------
 monitoring:
@@ -62,7 +61,6 @@ monitoring:
 --------------------
 <1> This setting identifies the hosts and port numbers of {es} nodes
 that are part of the monitoring cluster.
---
 
 . {kibana-ref}/monitoring-xpack-kibana.html[Configure monitoring in {kib}].
 

docs/copied-from-beats/shared-ssl-config.asciidoc

@@ -6,7 +6,7 @@ You can specify SSL options when you configure:
 * <<configuring-output,outputs>> that support SSL
 ifeval::["{beatname_lc}"!="apm-server"]
 * the <<setup-kibana-endpoint,Kibana endpoint>>
-endif::["{beatname_lc}"!="apm-server"]
+endif::[]
 ifeval::["{beatname_lc}"=="heartbeat"]
 * <<configuration-heartbeat-options,{beatname_uc} monitors>> that support SSL
 endif::[]