Merge pull request #11139 from aibaars/docs-update

Ruby: docs add missing entry

Author: aibaars

docs/codeql/codeql-language-guides/codeql-for-ruby.rst

@@ -21,3 +21,5 @@ Experiment and learn how to write effective and efficient queries for CodeQL dat
 -  :doc:`Analyzing data flow in Ruby <analyzing-data-flow-in-ruby>`: You can use CodeQL to track the flow of data through a Ruby program to places where the data is used.
 
 -  :doc:`Using API graphs in Ruby <using-api-graphs-in-ruby>`: API graphs are a uniform interface for referring to functions, classes, and methods defined in external libraries.
+
+-  :doc:`Abstract syntax tree classes for working with Ruby programs <abstract-syntax-tree-classes-for-working-with-ruby-programs>`: CodeQL has a large selection of classes for representing the abstract syntax tree of Ruby programs.