[Alerting][Docs] Removing placeholder sections in docs

docs/user/alerting/alerting-getting-started.asciidoc

@@ -136,9 +136,4 @@ Functionally, {kib} alerting differs in that:
 At a higher level, {kib} alerting allows rich integrations across use cases like <<xpack-apm,*APM*>>, <<metrics-app,*Metrics*>>, <<xpack-siem,*Security*>>, and <<uptime-app,*Uptime*>>.
 Pre-packaged *rule types* simplify setup and hide the details of complex, domain-specific detections, while providing a consistent interface across {kib}.
 
-[float]
-[[alerting-setup-prerequisites]]
-== Prerequisites
-<<alerting-prerequisites, Alerting prerequisites>> 
-
 --

docs/user/alerting/alerting-setup.asciidoc

@@ -1,8 +1,8 @@
 [role="xpack"]
 [[alerting-setup]]
-== Alerting Setup
+== Alerting Set up
 ++++
-<titleabbrev>Setup</titleabbrev>
+<titleabbrev>Set up</titleabbrev>
 ++++
 
 The Alerting feature is automatically enabled in {kib}, but might require some additional configuration.

docs/user/alerting/index.asciidoc

@@ -1,7 +1,5 @@
 include::alerting-getting-started.asciidoc[]
 include::alerting-setup.asciidoc[]
 include::create-and-manage-rules.asciidoc[]
-include::defining-rules.asciidoc[]
-include::rule-management.asciidoc[]
 include::rule-types.asciidoc[]
 include::alerting-troubleshooting.asciidoc[]

docs/user/alerting/rule-types.asciidoc

@@ -15,7 +15,7 @@ see {subscriptions}[the subscription page].
 [[stack-rules]]
 === Stack rules
 
-<<alert-management, Stack rules>> are built into {kib}.  To access the *Stack Rules* feature and create and edit rules, users require the `all` privilege. See <<kibana-feature-privileges, feature privileges>> for more information.
+<<create-and-manage-rules, Stack rules>> are built into {kib}.  To access the *Stack Rules* feature and create and edit rules, users require the `all` privilege. See <<kibana-feature-privileges, feature privileges>> for more information.
 
 [cols="2*<"]
 |===