[3.6] bpo-29910: IDLE no longer deletes a character after commenting out a region (GH-825) (#2429)

This happened because shortcut has a class binding and 'break' was not returned.
Fix other potential conflicts between IDLE and default key bindings.

* Add news item

* Update NEWS
(cherry picked from commit 213ce12)

1 files changed, 6 insertions, 4 deletions

diff --git a/Lib/idlelib/parenmatch.py b/Lib/idlelib/parenmatch.py
index ccec708..dcec34c 100644
--- a/Lib/idlelib/parenmatch.py
+++ b/Lib/idlelib/parenmatch.py
@@ -94,26 +94,28 @@ class ParenMatch:
                    .get_surrounding_brackets())
         if indices is None:
             self.bell()
-            return
+            return "break"
         self.activate_restore()
         self.create_tag(indices)
         self.set_timeout_last()
+        return "break"
 
     def paren_closed_event(self, event):
         # If it was a shortcut and not really a closing paren, quit.
         closer = self.text.get("insert-1c")
         if closer not in _openers:
-            return
+            return "break"
         hp = HyperParser(self.editwin, "insert-1c")
         if not hp.is_in_code():
-            return
+            return "break"
         indices = hp.get_surrounding_brackets(_openers[closer], True)
         if indices is None:
             self.bell()
-            return
+            return "break"
         self.activate_restore()
         self.create_tag(indices)
         self.set_timeout()
+        return "break"
 
     def restore_event(self, event=None):
         self.text.tag_delete("paren")