Docs: improve accuracy of pdb alias example (GH-102892)

(cherry picked from commit e0c63b72671bf816d3073f1a6a9107f6c171cae7)

Co-authored-by: gaogaotiantian <gaogaotiantian@hotmail.com>
diff --git a/Doc/library/pdb.rst b/Doc/library/pdb.rst
index 21c6ca8..5988477 100644
--- a/Doc/library/pdb.rst
+++ b/Doc/library/pdb.rst
@@ -513,7 +513,7 @@
    :file:`.pdbrc` file)::
 
       # Print instance variables (usage "pi classInst")
-      alias pi for k in %1.__dict__.keys(): print("%1.",k,"=",%1.__dict__[k])
+      alias pi for k in %1.__dict__.keys(): print(f"%1.{k} = {%1.__dict__[k]}")
       # Print instance variables in self
       alias ps pi self