Adds not to CodegenComposedSchemas and uses it in python-exp (#12146)

Updates docs

docs/generators/kotlin-server.md

@@ -260,6 +260,10 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |Composite|✓|OAS2,OAS3
 |Polymorphism|✗|OAS2,OAS3
 |Union|✗|OAS3
+|allOf|✗|OAS2,OAS3
+|anyOf|✗|OAS3
+|oneOf|✗|OAS3
+|not|✗|OAS3
 
 ### Security Feature
 | Name | Supported | Defined By |