Re-add "debugger" label, it is used in pydoc-topics.
diff --git a/Doc/library/pdb.rst b/Doc/library/pdb.rst
index cab4569..98b23f6 100644
--- a/Doc/library/pdb.rst
+++ b/Doc/library/pdb.rst
@@ -1,3 +1,5 @@
+.. _debugger:
+
 :mod:`pdb` --- The Python Debugger
 ==================================