[3.6] bpo-29919 Remove unused imports from idlelib [GH-137] (#2105)

Part of patch by Victor Stinner.
(cherry-pick from d6debb24e06152a827769b0cac24c47deccdeac1)
diff --git a/Lib/idlelib/config.py b/Lib/idlelib/config.py
index 358bee4..6a9fc61 100644
--- a/Lib/idlelib/config.py
+++ b/Lib/idlelib/config.py
@@ -29,7 +29,7 @@
 import os
 import sys
 
-from tkinter.font import Font, nametofont
+from tkinter.font import Font
 
 class InvalidConfigType(Exception): pass
 class InvalidConfigSet(Exception): pass