bpo-37903: IDLE: add shell sidebar mouse interactions (GH-25708)

Left click and drag to select lines.  With selection, right click for context menu with copy and copy-with-prompts.
Also add copy-with-prompts to the text-box context menu.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
diff --git a/Lib/idlelib/autocomplete_w.py b/Lib/idlelib/autocomplete_w.py
index fe7a6be..d3d1e69 100644
--- a/Lib/idlelib/autocomplete_w.py
+++ b/Lib/idlelib/autocomplete_w.py
@@ -26,9 +26,11 @@
 
 class AutoCompleteWindow:
 
-    def __init__(self, widget):
+    def __init__(self, widget, tags):
         # The widget (Text) on which we place the AutoCompleteWindow
         self.widget = widget
+        # Tags to mark inserted text with
+        self.tags = tags
         # The widgets we create
         self.autocompletewindow = self.listbox = self.scrollbar = None
         # The default foreground and background of a selection. Saved because
@@ -69,7 +71,8 @@ def _change_start(self, newstart):
                                "%s+%dc" % (self.startindex, len(self.start)))
         if i < len(newstart):
             self.widget.insert("%s+%dc" % (self.startindex, i),
-                               newstart[i:])
+                               newstart[i:],
+                               self.tags)
         self.start = newstart
 
     def _binary_search(self, s):