[8.16][serverless] Adds Knowledge Base page and updates AI Assistant doc

Author: benironside

docs/AI-for-security/ai-for-security.asciidoc

@@ -9,6 +9,8 @@
 You can use {elastic-sec}'s built-in AI tools to speed up your work and augment your team's capabilities. The pages in this section describe <<security-assistant, AI Assistant>>, which answers questions and enhances your workflows throughout {elastic-sec}, and <<attack-discovery, Attack discovery>>, which speeds up the triage process by finding patterns and identifying attacks spanning multiple alerts.
 
 include::ai-security-assistant.asciidoc[leveloffset=+1]
+include::knowledge-base.asciidoc[leveloffset=+2]
+
 include::attack-discovery.asciidoc[leveloffset=+1]
 
 include::connector-guides-landing-pg.asciidoc[leveloffset=+1]

docs/AI-for-security/knowledge-base.asciidoc

@@ -28,7 +28,12 @@
       "slug": "/serverless/security/ai-for-security",
       "items": [
         {
-          "slug": "/serverless/security/ai-assistant"
+          "slug": "/serverless/security/ai-assistant",
+          "items": [
+            {
+              "slug": "/serverless/security/ai-assistant-knowledge-base"
+            }
+          ]
         },  
         {
           "slug": "/serverless/security/attack-discovery"