Include new query system in doc builds.

For now these are in the "internal" section of the docs; the direct
query driver always will be.

doc/lsst.daf.butler/index.rst

@@ -173,6 +173,31 @@ Datastore utilities
    :headings: ^"
    :skip: Datastore
 
+Queries
+-------
+
+.. This section should move out of the "Middleware-Internal API" section when.
+   we release the new query system by renaming Butler._query to Butler.query.
+
+.. automodapi:: lsst.daf.butler.queries
+   :no-main-docstr:
+   :no-inherited-members:
+   :headings: ^"
+
+.. automodapi:: lsst.daf.butler.queries.tree
+   :no-main-docstr:
+   :no-inherited-members:
+   :headings: ^"
+   :skip: InvalidQueryError
+
+Direct butler query driver
+---------------------------
+
+.. automodapi:: lsst.daf.butler.direct_query_driver
+   :no-main-docstr:
+   :no-inherited-members:
+   :headings: ^"
+
 Registry utilities and interfaces
 ---------------------------------