Adds discrete attributes to installation and upgrade guide

Author: lcawl

docs/en/install-upgrade/installing-stack.asciidoc

@@ -30,6 +30,7 @@ select Kibana 5.1.2, Logstash 5.1.2, and Beats 5.1.2.
 |{branch}
 |===
 
+[discrete]
 [[install-order-elastic-stack]]
 === Installation Order
 
@@ -65,6 +66,7 @@ The table below lists the installation instructions, per component:
 |{hadoopref}/float.html[Installing Elasticsearch Hadoop {branch}]
 |===
 
+[discrete]
 [[install-elastic-stack-for-elastic-cloud]]
 === Installing on Elastic Cloud
 

docs/en/install-upgrade/upgrading-stack.asciidoc

@@ -10,6 +10,7 @@ Each component serves a particular role in the Elastic Stack. For some use cases
 use a subset of components in the Elastic Stack. For example, you might use Elasticsearch,
 Logstash, and Kibana; Elasticsearch and Kibana; Elasticsearch and Beats; or just Elasticsearch.
 
+[discrete]
 [[upgrading-elastic-stack-audience]]
 === Intended Audience
 
@@ -63,6 +64,7 @@ WARNING: This includes system indices, such as the `.kibana` index that is creat
 When upgrading from two major releases ago, it is important to read the breaking changes from
 1.x to 2.x, as well as from 2.x to 5.x!
 
+[discrete]
 [[upgrade-order-elastic-stack]]
 === Upgrade Order
 
@@ -124,6 +126,7 @@ that you are upgrading.
 |{hadoopref}/install.html[Upgrading to Elasticsearch Hadoop {branch}]
 |===
 
+[discrete]
 [[upgrade-elastic-stack-for-elastic-cloud]]
 === Upgrading on Elastic Cloud