Issue #27156: Remove obsolete code not used by IDLE.

help.txt, replaced by help.html, is out-of-date and should not be used.
Its dedicated viewer has be replaced by the html viewer in help.py.
'import idlever; I = idlever.IDLE_VERSION' is the same as
'import sys; I = version[:version.index(' ')]'

Lib/idlelib/editor.py

@@ -40,54 +40,6 @@ def _sphinx_version():
     return release
 
 
-class HelpDialog(object):
-
-    def __init__(self):
-        self.parent = None      # parent of help window
-        self.dlg = None         # the help window iteself
-
-    def display(self, parent, near=None):
-        """ Display the help dialog.
-
-            parent - parent widget for the help window
-
-            near - a Toplevel widget (e.g. EditorWindow or PyShell)
-                   to use as a reference for placing the help window
-        """
-        import warnings as w
-        w.warn("EditorWindow.HelpDialog is no longer used by Idle.\n"
-               "It will be removed in 3.6 or later.\n"
-               "It has been replaced by private help.HelpWindow\n",
-               DeprecationWarning, stacklevel=2)
-        if self.dlg is None:
-            self.show_dialog(parent)
-        if near:
-            self.nearwindow(near)
-
-    def show_dialog(self, parent):
-        self.parent = parent
-        fn=os.path.join(os.path.abspath(os.path.dirname(__file__)),'help.txt')
-        self.dlg = dlg = textview.view_file(parent,'Help',fn, modal=False)
-        dlg.bind('<Destroy>', self.destroy, '+')
-
-    def nearwindow(self, near):
-        # Place the help dialog near the window specified by parent.
-        # Note - this may not reposition the window in Metacity
-        #  if "/apps/metacity/general/disable_workarounds" is enabled
-        dlg = self.dlg
-        geom = (near.winfo_rootx() + 10, near.winfo_rooty() + 10)
-        dlg.withdraw()
-        dlg.geometry("=+%d+%d" % geom)
-        dlg.deiconify()
-        dlg.lift()
-
-    def destroy(self, ev=None):
-        self.dlg = None
-        self.parent = None
-
-helpDialog = HelpDialog()  # singleton instance, no longer used
-
-
 class EditorWindow(object):
     from idlelib.percolator import Percolator
     from idlelib.colorizer import ColorDelegator, color_config