[DOCS] Add alias glossary term (#1664)

Author: jrodewig

docs/en/glossary/glossary.asciidoc

@@ -32,6 +32,13 @@ this makes it easier to manage many agents at scale.
 See {fleet-guide}/agent-policy.html[{agent} policies].
 //Source: Observability
 
+[[glossary-alias]] alias::
++
+--
+[[glossary-index-alias]]
+include::{es-repo-dir}/glossary.asciidoc[tag=alias-def]
+--
+
 [[glossary-allocator]] allocator::
 Manages hosts that contain {es} and {kib} nodes. Controls the lifecycle of these
 nodes by creating new <<glossary-container,containers>> and managing the nodes
@@ -607,12 +614,6 @@ include::{es-repo-dir}/glossary.asciidoc[tag=id-def]
 include::{es-repo-dir}/glossary.asciidoc[tag=index-def]
 --
 
-[[glossary-index-alias]] index alias::
-+
---
-include::{es-repo-dir}/glossary.asciidoc[tag=index-alias-def]
---
-
 [[glossary-index-lifecycle]] index lifecycle::
 +
 --