Added custom kb docs and trieve migration docs (#682)

* Added custom kb docs and trieve migration docs

* updated gemini-1.5 note

* updated the query tool docs

* updated the docs

Author: ramsrib

fern/docs.yml

@@ -214,9 +214,12 @@ navigation:
                   - page: Query tool
                     path: knowledge-base/using-query-tool.mdx
                     icon: fa-light fa-magnifying-glass
-                  - page: Trieve integration
-                    path: knowledge-base/integrating-with-trieve.mdx
-                    icon: fa-light fa-brain
+                  - page: Custom knowledge base
+                    path: knowledge-base/custom-knowledge-base.mdx
+                    icon: fa-light fa-server
+                  - page: Migrating from Trieve
+                    path: knowledge-base/migrating-from-trieve.mdx
+                    icon: fa-light fa-triangle-exclamation
           - section: Structured outputs
             icon: fa-light fa-database
             path: assistants/structured-outputs.mdx