Issue #16853: Add new selectors module.
diff --git a/Doc/library/concurrency.rst b/Doc/library/concurrency.rst
index f2a512f..2d69107 100644
--- a/Doc/library/concurrency.rst
+++ b/Doc/library/concurrency.rst
@@ -21,6 +21,7 @@
    sched.rst
    queue.rst
    select.rst
+   selectors.rst
 
 
 The following are support modules for some of the above services: