Issue #22558: Add remaining doc links to source code for Python-coded modules.
Reformat header above separator line (added if missing) to a common format.
Patch by Yoni Lavi.
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index 037f11d..5212131 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -1,13 +1,13 @@
 :mod:`warnings` --- Warning control
 ===================================
 
-.. index:: single: warnings
-
 .. module:: warnings
    :synopsis: Issue warning messages and control their disposition.
 
 **Source code:** :source:`Lib/warnings.py`
 
+.. index:: single: warnings
+
 --------------
 
 Warning messages are typically issued in situations where it is useful to alert